diff --git a/components/util/str.rs b/components/util/str.rs
index 9c1ddf51fef..de3b5eb42b9 100644
--- a/components/util/str.rs
+++ b/components/util/str.rs
@@ -367,7 +367,7 @@ pub fn parse_length(mut value: &str) -> LengthOrPercentageOrAuto {
     }
 
     match FromStr::from_str(value) {
-        Ok(number) => LengthOrPercentageOrAuto::Length(Au::from_px(number)),
+        Ok(number) => LengthOrPercentageOrAuto::Length(Au::from_f64_px(number)),
         Err(_) => LengthOrPercentageOrAuto::Auto,
     }
 }
diff --git a/tests/unit/util/str.rs b/tests/unit/util/str.rs
index c20db9b604d..a9069a8dca2 100644
--- a/tests/unit/util/str.rs
+++ b/tests/unit/util/str.rs
@@ -17,6 +17,7 @@ pub fn test_parse_length() {
     check("0", LengthOrPercentageOrAuto::Length(Au::from_px(0)));
     check("0.000%", LengthOrPercentageOrAuto::Percentage(0.0));
     check("+5.82%", LengthOrPercentageOrAuto::Percentage(0.0582));
+    check("5.82", LengthOrPercentageOrAuto::Length(Au::from_f64_px(5.82)));
     check("invalid", LengthOrPercentageOrAuto::Auto);
     check("12 followed by invalid", LengthOrPercentageOrAuto::Length(Au::from_px(12)));
 }
diff --git a/tests/wpt/web-platform-tests/html/rendering/non-replaced-elements/the-hr-element-0/width-ref.html b/tests/wpt/web-platform-tests/html/rendering/non-replaced-elements/the-hr-element-0/width-ref.html
index 906846b3099..245fde9966f 100644
--- a/tests/wpt/web-platform-tests/html/rendering/non-replaced-elements/the-hr-element-0/width-ref.html
+++ b/tests/wpt/web-platform-tests/html/rendering/non-replaced-elements/the-hr-element-0/width-ref.html
@@ -11,6 +11,7 @@
 <div class=hr style="width: 100px"></div>
 <div class=hr style="width: 100px"></div>
 <div class=hr style="width: 100px"></div>
+<div class=hr style="width: 100.99px"></div>
 <div class=hr style="width: 0%"></div>
 <div class=hr style="width: 0%"></div>
 <div class=hr style="width: 0%"></div>
diff --git a/tests/wpt/web-platform-tests/html/rendering/non-replaced-elements/the-hr-element-0/width.html b/tests/wpt/web-platform-tests/html/rendering/non-replaced-elements/the-hr-element-0/width.html
index 3cd516ad70c..a436d2ae25a 100644
--- a/tests/wpt/web-platform-tests/html/rendering/non-replaced-elements/the-hr-element-0/width.html
+++ b/tests/wpt/web-platform-tests/html/rendering/non-replaced-elements/the-hr-element-0/width.html
@@ -7,6 +7,7 @@
 <hr width='100'>
 <hr width='100foo'>
 <hr width='  100    '>
+<hr width='100.99'>
 <hr width='0'>
 <hr width='00'>
 <hr width='+0'>