diff --git a/components/layout_2020/flow/mod.rs b/components/layout_2020/flow/mod.rs
index f877e702dfe..7321b602d52 100644
--- a/components/layout_2020/flow/mod.rs
+++ b/components/layout_2020/flow/mod.rs
@@ -21,8 +21,7 @@ use rayon_croissant::ParallelIteratorExt;
 use servo_arc::Arc;
 use style::computed_values::position::T as Position;
 use style::properties::ComputedValues;
-use style::values::computed::{Length, LengthOrAuto, LengthPercentage, LengthPercentageOrAuto};
-use style::values::generics::length::MaxSize;
+use style::values::computed::{Length, LengthOrAuto};
 use style::Zero;
 
 mod construct;
@@ -365,10 +364,14 @@ fn layout_in_flow_non_replaced_block_level<'a>(
     let pb = &padding + &border;
     let pb_inline_sum = pb.inline_sum();
 
-    let box_size = percent_resolved_box_size(style.box_size(), containing_block);
-    let max_box_size = percent_resolved_max_box_size(style.max_box_size(), containing_block);
-    let min_box_size =
-        percent_resolved_box_size(style.min_box_size(), containing_block).auto_is(Length::zero);
+    let box_size = style.box_size().percentages_relative_to(containing_block);
+    let max_box_size = style
+        .max_box_size()
+        .percentages_relative_to(containing_block);
+    let min_box_size = style
+        .min_box_size()
+        .percentages_relative_to(containing_block)
+        .auto_is(Length::zero);
 
     // https://drafts.csswg.org/css2/visudet.html#min-max-widths
     let solve_inline_margins = |inline_size| {
@@ -529,10 +532,14 @@ fn layout_in_flow_replaced_block_level<'a>(
     // FIXME(nox): This can divide by zero.
     let intrinsic_ratio = intrinsic_size.inline.px() / intrinsic_size.block.px();
 
-    let box_size = percent_resolved_box_size(style.box_size(), containing_block);
-    let min_box_size =
-        percent_resolved_box_size(style.min_box_size(), containing_block).auto_is(Length::zero);
-    let max_box_size = percent_resolved_max_box_size(style.max_box_size(), containing_block);
+    let box_size = style.box_size().percentages_relative_to(containing_block);
+    let min_box_size = style
+        .min_box_size()
+        .percentages_relative_to(containing_block)
+        .auto_is(Length::zero);
+    let max_box_size = style
+        .max_box_size()
+        .percentages_relative_to(containing_block);
 
     let clamp = |inline_size: Length, block_size: Length| {
         (
@@ -701,37 +708,3 @@ fn solve_inline_margins_for_in_flow_block_level(
         (LengthOrAuto::LengthPercentage(start), _) => (start, inline_margins - start),
     }
 }
-
-fn percent_resolved_box_size(
-    box_size: Vec2<LengthPercentageOrAuto>,
-    containing_block: &ContainingBlock,
-) -> Vec2<LengthOrAuto> {
-    Vec2 {
-        inline: box_size
-            .inline
-            .percentage_relative_to(containing_block.inline_size),
-        block: box_size
-            .block
-            .maybe_percentage_relative_to(containing_block.block_size.non_auto()),
-    }
-}
-
-fn percent_resolved_max_box_size(
-    max_box_size: Vec2<MaxSize<LengthPercentage>>,
-    containing_block: &ContainingBlock,
-) -> Vec2<Option<Length>> {
-    Vec2 {
-        inline: match max_box_size.inline {
-            MaxSize::LengthPercentage(max_inline_size) => {
-                Some(max_inline_size.percentage_relative_to(containing_block.inline_size))
-            },
-            MaxSize::None => None,
-        },
-        block: match max_box_size.block {
-            MaxSize::LengthPercentage(max_block_size) => {
-                max_block_size.maybe_percentage_relative_to(containing_block.block_size.non_auto())
-            },
-            MaxSize::None => None,
-        },
-    }
-}
diff --git a/components/layout_2020/geom.rs b/components/layout_2020/geom.rs
index 2eafb78051e..562fad5c4f6 100644
--- a/components/layout_2020/geom.rs
+++ b/components/layout_2020/geom.rs
@@ -2,11 +2,13 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use crate::ContainingBlock;
 use std::fmt;
 use std::ops::{Add, AddAssign, Sub};
 use style::logical_geometry::{BlockFlowDirection, InlineBaseDirection};
 use style::logical_geometry::{PhysicalCorner, WritingMode};
 use style::values::computed::{Length, LengthOrAuto, LengthPercentage, LengthPercentageOrAuto};
+use style::values::generics::length::MaxSize;
 use style::Zero;
 use style_traits::CSSPixel;
 
@@ -151,6 +153,39 @@ impl flow_relative::Vec2<LengthOrAuto> {
     }
 }
 
+impl flow_relative::Vec2<LengthPercentageOrAuto> {
+    pub fn percentages_relative_to(
+        &self,
+        containing_block: &ContainingBlock,
+    ) -> flow_relative::Vec2<LengthOrAuto> {
+        flow_relative::Vec2 {
+            inline: self
+                .inline
+                .percentage_relative_to(containing_block.inline_size),
+            block: self
+                .block
+                .maybe_percentage_relative_to(containing_block.block_size.non_auto()),
+        }
+    }
+}
+
+impl flow_relative::Vec2<MaxSize<LengthPercentage>> {
+    pub fn percentages_relative_to(
+        &self,
+        containing_block: &ContainingBlock,
+    ) -> flow_relative::Vec2<Option<Length>> {
+        flow_relative::Vec2 {
+            inline: self
+                .inline
+                .to_option()
+                .map(|lp| lp.percentage_relative_to(containing_block.inline_size)),
+            block: self.block.to_option().and_then(|olp| {
+                olp.maybe_percentage_relative_to(containing_block.block_size.non_auto())
+            }),
+        }
+    }
+}
+
 impl flow_relative::Rect<Length> {
     pub fn zero() -> Self {
         Self {
diff --git a/components/style/values/generics/length.rs b/components/style/values/generics/length.rs
index 4183f40a942..b2f34058283 100644
--- a/components/style/values/generics/length.rs
+++ b/components/style/values/generics/length.rs
@@ -207,6 +207,15 @@ impl<LengthPercentage> MaxSize<LengthPercentage> {
     pub fn none() -> Self {
         MaxSize::None
     }
+
+    /// Convert
+    #[cfg(not(feature = "gecko"))]
+    pub fn to_option(self) -> Option<LengthPercentage> {
+        match self {
+            Self::LengthPercentage(lp) => Some(lp),
+            Self::None => None,
+        }
+    }
 }
 
 /// A generic `<length>` | `<number>` value for the `-moz-tab-size` property.