diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 2ca775ed345..e0003ceae30 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -4,7 +4,6 @@
 
 //! Element nodes.
 
-use app_units::Au;
 use cssparser::Color;
 use devtools_traits::AttrInfo;
 use dom::activation::Activatable;
@@ -476,7 +475,7 @@ impl LayoutElementHelpers for LayoutJS<Element> {
         };
 
         if let Some(cellspacing) = cellspacing {
-            let width_value = specified::Length::Absolute(Au::from_px(cellspacing as i32));
+            let width_value = specified::Length::from_px(cellspacing as f32);
             hints.push(from_declaration(
                 PropertyDeclaration::BorderSpacing(DeclaredValue::Value(
                     border_spacing::SpecifiedValue {
@@ -509,7 +508,8 @@ impl LayoutElementHelpers for LayoutJS<Element> {
         };
 
         if let Some(size) = size {
-            let value = specified::Length::ServoCharacterWidth(specified::CharacterWidth(size));
+            let value = specified::Length::NoCalc(
+                specified::NoCalcLength::ServoCharacterWidth(specified::CharacterWidth(size)));
             hints.push(from_declaration(
                 PropertyDeclaration::Width(DeclaredValue::Value(
                     specified::LengthOrPercentageOrAuto::Length(value)))));
@@ -541,7 +541,7 @@ impl LayoutElementHelpers for LayoutJS<Element> {
             }
             LengthOrPercentageOrAuto::Length(length) => {
                 let width_value = specified::LengthOrPercentageOrAuto::Length(
-                    specified::Length::Absolute(length));
+                    specified::Length::NoCalc(specified::NoCalcLength::Absolute(length)));
                 hints.push(from_declaration(
                     PropertyDeclaration::Width(DeclaredValue::Value(width_value))));
             }
@@ -566,7 +566,7 @@ impl LayoutElementHelpers for LayoutJS<Element> {
             }
             LengthOrPercentageOrAuto::Length(length) => {
                 let height_value = specified::LengthOrPercentageOrAuto::Length(
-                    specified::Length::Absolute(length));
+                    specified::Length::NoCalc(specified::NoCalcLength::Absolute(length)));
                 hints.push(from_declaration(
                     PropertyDeclaration::Height(DeclaredValue::Value(height_value))));
             }
@@ -588,7 +588,8 @@ impl LayoutElementHelpers for LayoutJS<Element> {
             // scrollbar size into consideration (but we don't have a scrollbar yet!)
             //
             // https://html.spec.whatwg.org/multipage/#textarea-effective-width
-            let value = specified::Length::ServoCharacterWidth(specified::CharacterWidth(cols));
+            let value = specified::Length::NoCalc(
+                specified::NoCalcLength::ServoCharacterWidth(specified::CharacterWidth(cols)));
             hints.push(from_declaration(
                 PropertyDeclaration::Width(DeclaredValue::Value(
                     specified::LengthOrPercentageOrAuto::Length(value)))));
@@ -608,7 +609,8 @@ impl LayoutElementHelpers for LayoutJS<Element> {
             // TODO(mttr) This should take scrollbar size into consideration.
             //
             // https://html.spec.whatwg.org/multipage/#textarea-effective-height
-            let value = specified::Length::FontRelative(specified::FontRelativeLength::Em(rows as CSSFloat));
+            let value = specified::Length::NoCalc(
+                specified::NoCalcLength::FontRelative(specified::FontRelativeLength::Em(rows as CSSFloat)));
             hints.push(from_declaration(
                 PropertyDeclaration::Height(DeclaredValue::Value(
                         specified::LengthOrPercentageOrAuto::Length(value)))));
@@ -622,8 +624,7 @@ impl LayoutElementHelpers for LayoutJS<Element> {
         };
 
         if let Some(border) = border {
-            let width_value = specified::BorderWidth::from_length(
-                specified::Length::Absolute(Au::from_px(border as i32)));
+            let width_value = specified::BorderWidth::from_length(specified::Length::from_px(border as f32));
             hints.push(from_declaration(
                 PropertyDeclaration::BorderTopWidth(DeclaredValue::Value(width_value.clone()))));
             hints.push(from_declaration(
diff --git a/components/style/properties/longhand/box.mako.rs b/components/style/properties/longhand/box.mako.rs
index 754afaf164d..9bec8f87b21 100644
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@@ -1328,7 +1328,7 @@ ${helpers.single_keyword("animation-fill-mode",
                         result.push(SpecifiedOperation::Translate(TranslateKind::Translate,
                                                                   tx,
                                                                   ty,
-                                                                  specified::Length::Absolute(Au(0))));
+                                                                  specified::Length::zero()));
                         Ok(())
                     }))
                 },
@@ -1339,7 +1339,7 @@ ${helpers.single_keyword("animation-fill-mode",
                             TranslateKind::TranslateX,
                             tx,
                             specified::LengthOrPercentage::zero(),
-                            specified::Length::Absolute(Au(0))));
+                            specified::Length::zero()));
                         Ok(())
                     }))
                 },
@@ -1350,7 +1350,7 @@ ${helpers.single_keyword("animation-fill-mode",
                             TranslateKind::TranslateY,
                             specified::LengthOrPercentage::zero(),
                             ty,
-                            specified::Length::Absolute(Au(0))));
+                            specified::Length::zero()));
                         Ok(())
                     }))
                 },
@@ -1836,7 +1836,7 @@ ${helpers.single_keyword("transform-style",
         Ok(SpecifiedValue {
             horizontal: result.horizontal.unwrap_or(LengthOrPercentage::Percentage(Percentage(0.5))),
             vertical: result.vertical.unwrap_or(LengthOrPercentage::Percentage(Percentage(0.5))),
-            depth: result.depth.unwrap_or(Length::Absolute(Au(0))),
+            depth: result.depth.unwrap_or(Length::zero()),
         })
     }
 
diff --git a/components/style/properties/longhand/effects.mako.rs b/components/style/properties/longhand/effects.mako.rs
index 3da52aa3db2..01771f36315 100644
--- a/components/style/properties/longhand/effects.mako.rs
+++ b/components/style/properties/longhand/effects.mako.rs
@@ -280,10 +280,10 @@ ${helpers.predefined_type("opacity",
                 left = try!(parse_argument(context, input));
             }
             Ok(SpecifiedValue(Some(SpecifiedClipRect {
-                top: top.unwrap_or(Length::Absolute(Au(0))),
+                top: top.unwrap_or(Length::zero()),
                 right: right,
                 bottom: bottom,
-                left: left.unwrap_or(Length::Absolute(Au(0))),
+                left: left.unwrap_or(Length::zero()),
             })))
         })
     }
diff --git a/components/style/properties/longhand/font.mako.rs b/components/style/properties/longhand/font.mako.rs
index d143398b2d8..3bb3a09db89 100644
--- a/components/style/properties/longhand/font.mako.rs
+++ b/components/style/properties/longhand/font.mako.rs
@@ -329,7 +329,7 @@ ${helpers.single_keyword("font-variant-caps",
     use std::fmt;
     use style_traits::ToCss;
     use values::{FONT_MEDIUM_PX, HasViewportPercentage};
-    use values::specified::{LengthOrPercentage, Length, Percentage};
+    use values::specified::{LengthOrPercentage, Length, NoCalcLength, Percentage};
 
     impl ToCss for SpecifiedValue {
         fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
@@ -363,10 +363,10 @@ ${helpers.single_keyword("font-variant-caps",
         #[inline]
         fn to_computed_value(&self, context: &Context) -> computed_value::T {
             match self.0 {
-                LengthOrPercentage::Length(Length::FontRelative(value)) => {
+                LengthOrPercentage::Length(Length::NoCalc(NoCalcLength::FontRelative(value))) => {
                     value.to_computed_value(context, /* use inherited */ true)
                 }
-                LengthOrPercentage::Length(Length::ServoCharacterWidth(value)) => {
+                LengthOrPercentage::Length(Length::NoCalc(NoCalcLength::ServoCharacterWidth(value))) => {
                     value.to_computed_value(context.inherited_style().get_font().clone_font_size())
                 }
                 LengthOrPercentage::Length(ref l) => {
diff --git a/components/style/properties/longhand/inherited_text.mako.rs b/components/style/properties/longhand/inherited_text.mako.rs
index db83c7308df..9c63fd45686 100644
--- a/components/style/properties/longhand/inherited_text.mako.rs
+++ b/components/style/properties/longhand/inherited_text.mako.rs
@@ -113,13 +113,14 @@
                         specified::LengthOrPercentage::Length(ref value) =>
                             computed_value::T::Length(value.to_computed_value(context)),
                         specified::LengthOrPercentage::Percentage(specified::Percentage(value)) => {
-                            let fr = specified::Length::FontRelative(specified::FontRelativeLength::Em(value));
+                            let fr = specified::Length::NoCalc(specified::NoCalcLength::FontRelative(
+                                specified::FontRelativeLength::Em(value)));
                             computed_value::T::Length(fr.to_computed_value(context))
                         },
                         specified::LengthOrPercentage::Calc(ref calc) => {
                             let calc = calc.to_computed_value(context);
                             let fr = specified::FontRelativeLength::Em(calc.percentage());
-                            let fr = specified::Length::FontRelative(fr);
+                            let fr = specified::Length::NoCalc(specified::NoCalcLength::FontRelative(fr));
                             computed_value::T::Length(calc.length() + fr.to_computed_value(context))
                         }
                     }
@@ -681,9 +682,7 @@ ${helpers.single_keyword("text-align-last",
 
     fn parse_one_text_shadow(context: &ParserContext, input: &mut Parser) -> Result<SpecifiedTextShadow,()> {
         use app_units::Au;
-        let mut lengths = [specified::Length::Absolute(Au(0)),
-                           specified::Length::Absolute(Au(0)),
-                           specified::Length::Absolute(Au(0))];
+        let mut lengths = [specified::Length::zero(), specified::Length::zero(), specified::Length::zero()];
         let mut lengths_parsed = false;
         let mut color = None;
 
diff --git a/components/style/properties/shorthand/inherited_text.mako.rs b/components/style/properties/shorthand/inherited_text.mako.rs
index a75e6d8925d..d2b0bce7d76 100644
--- a/components/style/properties/shorthand/inherited_text.mako.rs
+++ b/components/style/properties/shorthand/inherited_text.mako.rs
@@ -99,7 +99,7 @@
             Ok(Longhands {
                 _webkit_text_stroke_color: color.or(Some(CSSColor { parsed: CSSParserColor::CurrentColor,
                     authored: None })),
-                _webkit_text_stroke_width: width.or(Some(BorderWidth::from_length(Length::Absolute(Au::from_px(0))))),
+                _webkit_text_stroke_width: width.or(Some(BorderWidth::from_length(Length::zero()))),
             })
         } else {
             Err(())
diff --git a/components/style/properties/shorthand/position.mako.rs b/components/style/properties/shorthand/position.mako.rs
index 807bcadb5df..f9347ef33a1 100644
--- a/components/style/properties/shorthand/position.mako.rs
+++ b/components/style/properties/shorthand/position.mako.rs
@@ -57,7 +57,6 @@
 <%helpers:shorthand name="flex" sub_properties="flex-grow flex-shrink flex-basis" extra_prefixes="webkit"
                     spec="https://drafts.csswg.org/css-flexbox/#flex-property">
     use parser::Parse;
-    use app_units::Au;
     use values::specified::{Number, Length, LengthOrPercentageOrAutoOrContent};
 
     pub fn parse_flexibility(input: &mut Parser)
@@ -102,7 +101,7 @@
         Ok(Longhands {
             flex_grow: grow.or(Some(Number(1.0))),
             flex_shrink: shrink.or(Some(Number(1.0))),
-            flex_basis: basis.or(Some(LengthOrPercentageOrAutoOrContent::Length(Length::Absolute(Au(0)))))
+            flex_basis: basis.or(Some(LengthOrPercentageOrAutoOrContent::Length(Length::zero())))
         })
     }
 
diff --git a/components/style/values/specified/basic_shape.rs b/components/style/values/specified/basic_shape.rs
index d89f926dee4..c7175b5352d 100644
--- a/components/style/values/specified/basic_shape.rs
+++ b/components/style/values/specified/basic_shape.rs
@@ -327,7 +327,7 @@ fn serialize_basicshape_position<W>(position: &Position, dest: &mut W)
         // 0 length should be replaced with 0%
         fn replace_with_percent(input: LengthOrPercentage) -> LengthOrPercentage {
             match input {
-                LengthOrPercentage::Length(Length::Absolute(au)) if au.0 == 0 => {
+                LengthOrPercentage::Length(ref l) if l == &Length::zero() => {
                     LengthOrPercentage::Percentage(Percentage(0.0))
                 }
                 _ => {
diff --git a/components/style/values/specified/length.rs b/components/style/values/specified/length.rs
index f6d30655064..8e9a96067d6 100644
--- a/components/style/values/specified/length.rs
+++ b/components/style/values/specified/length.rs
@@ -316,6 +316,18 @@ impl NoCalcLength {
             _ => Err(())
         }
     }
+
+    #[inline]
+    /// Returns a `zero` length.
+    pub fn zero() -> NoCalcLength {
+        NoCalcLength::Absolute(Au(0))
+    }
+
+    /// Get an absolute length from a px values.
+    #[inline]
+    pub fn from_px(px_value: CSSFloat) -> NoCalcLength {
+        NoCalcLength::Absolute(Au((px_value * AU_PER_PX) as i32))
+    }
 }
 
 /// An extension to `NoCalcLength` to parse `calc` expressions.
@@ -395,6 +407,12 @@ impl Mul<CSSFloat> for ViewportPercentageLength {
 }
 
 impl Length {
+    #[inline]
+    /// Returns a `zero` length.
+    pub fn zero() -> Length {
+        Length::NoCalc(NoCalcLength::zero())
+    }
+
     /// https://drafts.csswg.org/css-fonts-3/#font-size-prop
     pub fn from_str(s: &str) -> Option<Length> {
         NoCalcLength::from_str(s).map(Length::NoCalc)
@@ -411,7 +429,7 @@ impl Length {
             Token::Dimension(ref value, ref unit) if context.is_ok(value.value) =>
                 Length::parse_dimension(value.value, unit),
             Token::Number(ref value) if value.value == 0. =>
-                Ok(Length::Absolute(Au(0))),
+                Ok(Length::zero()),
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") =>
                 input.parse_nested_block(|input| {
                     CalcLengthOrPercentage::parse_length(input, context)
@@ -428,7 +446,7 @@ impl Length {
     /// Get an absolute length from a px values.
     #[inline]
     pub fn from_px(px_value: CSSFloat) -> Length {
-        Length::NoCalc(NoCalcLength::Absolute(Au((px_value * AU_PER_PX) as i32)))
+        Length::NoCalc(NoCalcLength::from_px(px_value))
     }
 
     /// Extract inner length without a clone, replacing it with a 0 Au
@@ -436,8 +454,7 @@ impl Length {
     /// Use when you need to move out of a length array without cloning
     #[inline]
     pub fn take(&mut self) -> Self {
-        let new = Length::Absolute(Au(0));
-        mem::replace(self, new)
+        mem::replace(self, Length::zero())
     }
 }
 
@@ -473,7 +490,7 @@ pub struct CalcProductNode {
 #[derive(Clone, Debug)]
 #[allow(missing_docs)]
 pub enum CalcValueNode {
-    Length(Length),
+    Length(LengthInternal),
     Angle(Angle),
     Time(Time),
     Percentage(CSSFloat),
@@ -566,7 +583,7 @@ impl CalcLengthOrPercentage {
             (Token::Number(ref value), _) => Ok(CalcValueNode::Number(value.value)),
             (Token::Dimension(ref value, ref unit), CalcUnit::Length) |
             (Token::Dimension(ref value, ref unit), CalcUnit::LengthOrPercentage) => {
-                Length::parse_dimension(value.value, unit).map(CalcValueNode::Length)
+                LengthInternal::parse_dimension(value.value, unit).map(CalcValueNode::Length)
             }
             (Token::Dimension(ref value, ref unit), CalcUnit::Angle) => {
                 Angle::parse_dimension(value.value, unit).map(CalcValueNode::Angle)
@@ -907,9 +924,10 @@ impl ToCss for LengthOrPercentage {
     }
 }
 impl LengthOrPercentage {
+    #[inline]
     /// Returns a `zero` length.
     pub fn zero() -> LengthOrPercentage {
-        LengthOrPercentage::Length(Length::Absolute(Au(0)))
+        LengthOrPercentage::Length(Length::zero())
     }
 
     fn parse_internal(input: &mut Parser, context: AllowedNumericType)
@@ -921,7 +939,7 @@ impl LengthOrPercentage {
             Token::Percentage(ref value) if context.is_ok(value.unit_value) =>
                 Ok(LengthOrPercentage::Percentage(Percentage(value.unit_value))),
             Token::Number(ref value) if value.value == 0. =>
-                Ok(LengthOrPercentage::Length(Length::Absolute(Au(0)))),
+                Ok(LengthOrPercentage::Length(Length::zero())),
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
                 let calc = try!(input.parse_nested_block(CalcLengthOrPercentage::parse_length_or_percentage));
                 Ok(LengthOrPercentage::Calc(Box::new(calc)))
@@ -941,8 +959,7 @@ impl LengthOrPercentage {
     /// Use when you need to move out of a length array without cloning
     #[inline]
     pub fn take(&mut self) -> Self {
-        let new = LengthOrPercentage::Length(Length::Absolute(Au(0)));
-        mem::replace(self, new)
+        mem::replace(self, LengthOrPercentage::zero())
     }
 }
 
@@ -996,7 +1013,7 @@ impl LengthOrPercentageOrAuto {
             Token::Percentage(ref value) if context.is_ok(value.unit_value) =>
                 Ok(LengthOrPercentageOrAuto::Percentage(Percentage(value.unit_value))),
             Token::Number(ref value) if value.value == 0. =>
-                Ok(LengthOrPercentageOrAuto::Length(Length::Absolute(Au(0)))),
+                Ok(LengthOrPercentageOrAuto::Length(Length::zero())),
             Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") =>
                 Ok(LengthOrPercentageOrAuto::Auto),
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
@@ -1063,7 +1080,7 @@ impl LengthOrPercentageOrNone {
             Token::Percentage(ref value) if context.is_ok(value.unit_value) =>
                 Ok(LengthOrPercentageOrNone::Percentage(Percentage(value.unit_value))),
             Token::Number(ref value) if value.value == 0. =>
-                Ok(LengthOrPercentageOrNone::Length(Length::Absolute(Au(0)))),
+                Ok(LengthOrPercentageOrNone::Length(Length::zero())),
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
                 let calc = try!(input.parse_nested_block(CalcLengthOrPercentage::parse_length_or_percentage));
                 Ok(LengthOrPercentageOrNone::Calc(Box::new(calc)))
@@ -1146,7 +1163,7 @@ impl Parse for LengthOrPercentageOrAutoOrContent {
             Token::Percentage(ref value) if context.is_ok(value.unit_value) =>
                 Ok(LengthOrPercentageOrAutoOrContent::Percentage(Percentage(value.unit_value))),
             Token::Number(ref value) if value.value == 0. =>
-                Ok(LengthOrPercentageOrAutoOrContent::Length(Length::Absolute(Au(0)))),
+                Ok(LengthOrPercentageOrAutoOrContent::Length(Length::zero())),
             Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") =>
                 Ok(LengthOrPercentageOrAutoOrContent::Auto),
             Token::Ident(ref value) if value.eq_ignore_ascii_case("content") =>
diff --git a/components/style/values/specified/mod.rs b/components/style/values/specified/mod.rs
index 253237528bc..8a57f52d99a 100644
--- a/components/style/values/specified/mod.rs
+++ b/components/style/values/specified/mod.rs
@@ -198,7 +198,7 @@ impl NoViewportPercentage for BorderRadiusSize {}
 impl BorderRadiusSize {
     #[allow(missing_docs)]
     pub fn zero() -> BorderRadiusSize {
-        let zero = LengthOrPercentage::Length(Length::Absolute(Au(0)));
+        let zero = LengthOrPercentage::Length(Length::default());
             BorderRadiusSize(Size2D::new(zero.clone(), zero))
     }
 
@@ -605,12 +605,11 @@ impl Shadow {
     // disable_spread_and_inset is for filter: drop-shadow(...)
     #[allow(missing_docs)]
     pub fn parse(context:  &ParserContext, input: &mut Parser, disable_spread_and_inset: bool) -> Result<Shadow, ()> {
-        use app_units::Au;
         let length_count = if disable_spread_and_inset { 3 } else { 4 };
-        let mut lengths = [Length::Absolute(Au(0)),
-                           Length::Absolute(Au(0)),
-                           Length::Absolute(Au(0)),
-                           Length::Absolute(Au(0))];
+        let mut lengths = [Length::default(),
+                           Length::default(),
+                           Length::default(),
+                           Length::default()];
         let mut lengths_parsed = false;
         let mut color = None;
         let mut inset = false;
@@ -662,7 +661,7 @@ impl Shadow {
             offset_x: lengths[0].take(),
             offset_y: lengths[1].take(),
             blur_radius: lengths[2].take(),
-            spread_radius: if disable_spread_and_inset { Length::Absolute(Au(0)) } else { lengths[3].take() },
+            spread_radius: if disable_spread_and_inset { Length::default() } else { lengths[3].take() },
             color: color,
             inset: inset,
         })
diff --git a/components/style/viewport.rs b/components/style/viewport.rs
index 7e98b7e2460..eb2d0e99f4e 100644
--- a/components/style/viewport.rs
+++ b/components/style/viewport.rs
@@ -25,7 +25,7 @@ use style_traits::ToCss;
 use style_traits::viewport::{Orientation, UserZoom, ViewportConstraints, Zoom};
 use stylesheets::{Stylesheet, Origin};
 use values::computed::{Context, ToComputedValue};
-use values::specified::{Length, LengthOrPercentageOrAuto, ViewportPercentageLength};
+use values::specified::{Length, NoCalcLength, LengthOrPercentageOrAuto, ViewportPercentageLength};
 
 macro_rules! declare_viewport_descriptor {
     ( $( $variant_name: expr => $variant: ident($data: ident), )+ ) => {
@@ -150,9 +150,11 @@ impl FromMeta for ViewportLength {
 
         Some(match value {
             v if v.eq_ignore_ascii_case("device-width") =>
-                specified!(Length::ViewportPercentage(ViewportPercentageLength::Vw(100.))),
+                specified!(Length::NoCalc(
+                    NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vw(100.)))),
             v if v.eq_ignore_ascii_case("device-height") =>
-                specified!(Length::ViewportPercentage(ViewportPercentageLength::Vh(100.))),
+                specified!(Length::NoCalc(
+                    NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vh(100.)))),
             _ => {
                 match value.parse::<f32>() {
                     Ok(n) if n >= 0. => specified!(Length::from_px(n.max(1.).min(10000.))),
diff --git a/tests/unit/style/media_queries.rs b/tests/unit/style/media_queries.rs
index d6e32a9e5a5..11e1987928a 100644
--- a/tests/unit/style/media_queries.rs
+++ b/tests/unit/style/media_queries.rs
@@ -2,7 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use app_units::Au;
 use cssparser::{Parser, SourcePosition};
 use euclid::size::TypedSize2D;
 use servo_url::ServoUrl;
@@ -207,7 +206,7 @@ fn test_mq_default_expressions() {
         assert!(q.media_type == MediaQueryType::All, css.to_owned());
         assert!(q.expressions.len() == 1, css.to_owned());
         match *q.expressions[0].kind_for_testing() {
-            ExpressionKind::Width(Range::Min(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(100))),
+            ExpressionKind::Width(Range::Min(ref w)) => assert!(*w == specified::Length::from_px(100.)),
             _ => panic!("wrong expression type"),
         }
     });
@@ -219,7 +218,7 @@ fn test_mq_default_expressions() {
         assert!(q.media_type == MediaQueryType::All, css.to_owned());
         assert!(q.expressions.len() == 1, css.to_owned());
         match *q.expressions[0].kind_for_testing() {
-            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(43))),
+            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::from_px(43.)),
             _ => panic!("wrong expression type"),
         }
     });
@@ -234,7 +233,7 @@ fn test_mq_expressions() {
         assert!(q.media_type == MediaQueryType::Known(MediaType::Screen), css.to_owned());
         assert!(q.expressions.len() == 1, css.to_owned());
         match *q.expressions[0].kind_for_testing() {
-            ExpressionKind::Width(Range::Min(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(100))),
+            ExpressionKind::Width(Range::Min(ref w)) => assert!(*w == specified::Length::from_px(100.)),
             _ => panic!("wrong expression type"),
         }
     });
@@ -246,7 +245,7 @@ fn test_mq_expressions() {
         assert!(q.media_type == MediaQueryType::Known(MediaType::Print), css.to_owned());
         assert!(q.expressions.len() == 1, css.to_owned());
         match *q.expressions[0].kind_for_testing() {
-            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(43))),
+            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::from_px(43.)),
             _ => panic!("wrong expression type"),
         }
     });
@@ -258,7 +257,7 @@ fn test_mq_expressions() {
         assert!(q.media_type == MediaQueryType::Known(MediaType::Print), css.to_owned());
         assert!(q.expressions.len() == 1, css.to_owned());
         match *q.expressions[0].kind_for_testing() {
-            ExpressionKind::Width(Range::Eq(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(43))),
+            ExpressionKind::Width(Range::Eq(ref w)) => assert!(*w == specified::Length::from_px(43.)),
             _ => panic!("wrong expression type"),
         }
     });
@@ -270,7 +269,7 @@ fn test_mq_expressions() {
         assert!(q.media_type == MediaQueryType::Unknown(Atom::from("fridge")), css.to_owned());
         assert!(q.expressions.len() == 1, css.to_owned());
         match *q.expressions[0].kind_for_testing() {
-            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(52))),
+            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::from_px(52.)),
             _ => panic!("wrong expression type"),
         }
     });
@@ -295,11 +294,11 @@ fn test_mq_multiple_expressions() {
         assert!(q.media_type == MediaQueryType::All, css.to_owned());
         assert!(q.expressions.len() == 2, css.to_owned());
         match *q.expressions[0].kind_for_testing() {
-            ExpressionKind::Width(Range::Min(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(100))),
+            ExpressionKind::Width(Range::Min(ref w)) => assert!(*w == specified::Length::from_px(100.)),
             _ => panic!("wrong expression type"),
         }
         match *q.expressions[1].kind_for_testing() {
-            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(200))),
+            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::from_px(200.)),
             _ => panic!("wrong expression type"),
         }
     });
@@ -311,11 +310,11 @@ fn test_mq_multiple_expressions() {
         assert!(q.media_type == MediaQueryType::Known(MediaType::Screen), css.to_owned());
         assert!(q.expressions.len() == 2, css.to_owned());
         match *q.expressions[0].kind_for_testing() {
-            ExpressionKind::Width(Range::Min(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(100))),
+            ExpressionKind::Width(Range::Min(ref w)) => assert!(*w == specified::Length::from_px(100.)),
             _ => panic!("wrong expression type"),
         }
         match *q.expressions[1].kind_for_testing() {
-            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::Absolute(Au::from_px(200))),
+            ExpressionKind::Width(Range::Max(ref w)) => assert!(*w == specified::Length::from_px(200.)),
             _ => panic!("wrong expression type"),
         }
     });
diff --git a/tests/unit/style/properties/viewport.rs b/tests/unit/style/properties/viewport.rs
index 221e7d568bb..7e036a6e95d 100644
--- a/tests/unit/style/properties/viewport.rs
+++ b/tests/unit/style/properties/viewport.rs
@@ -6,21 +6,21 @@ use app_units::Au;
 use style::properties::{DeclaredValue, PropertyDeclaration};
 use style::properties::longhands::border_top_width;
 use style::values::HasViewportPercentage;
-use style::values::specified::{Length, ViewportPercentageLength};
+use style::values::specified::{Length, NoCalcLength, ViewportPercentageLength};
 
 #[test]
 fn has_viewport_percentage_for_specified_value() {
     //TODO: test all specified value with a HasViewportPercentage impl
     let pvw = PropertyDeclaration::BorderTopWidth(
         DeclaredValue::Value(border_top_width::SpecifiedValue::from_length(
-            Length::ViewportPercentage(ViewportPercentageLength::Vw(100.))
+            Length::NoCalc(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vw(100.)))
         ))
     );
     assert!(pvw.has_viewport_percentage());
 
     let pabs = PropertyDeclaration::BorderTopWidth(
         DeclaredValue::Value(border_top_width::SpecifiedValue::from_length(
-            Length::Absolute(Au(100))
+            Length::NoCalc(NoCalcLength::Absolute(Au(100)))
         ))
     );
     assert!(!pabs.has_viewport_percentage());
diff --git a/tests/unit/style/value.rs b/tests/unit/style/value.rs
index 4f9944e324d..472a5177d30 100644
--- a/tests/unit/style/value.rs
+++ b/tests/unit/style/value.rs
@@ -5,14 +5,14 @@
 use app_units::Au;
 use cssparser::Parser;
 use style::values::HasViewportPercentage;
-use style::values::specified::{ViewportPercentageLength, Length};
+use style::values::specified::{ViewportPercentageLength, NoCalcLength};
 use style::values::specified::length::{CalcLengthOrPercentage, CalcUnit};
 
 #[test]
 fn length_has_viewport_percentage() {
-    let l = Length::ViewportPercentage(ViewportPercentageLength::Vw(100.));
+    let l = NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vw(100.));
     assert!(l.has_viewport_percentage());
-    let l = Length::Absolute(Au(100));
+    let l = NoCalcLength::Absolute(Au(100));
     assert!(!l.has_viewport_percentage());
 }