diff --git a/Libraries/LibWeb/CSS/Serialize.cpp b/Libraries/LibWeb/CSS/Serialize.cpp
index fddc2dcc68b..3fea529a860 100644
--- a/Libraries/LibWeb/CSS/Serialize.cpp
+++ b/Libraries/LibWeb/CSS/Serialize.cpp
@@ -186,32 +186,49 @@ void serialize_a_srgb_value(StringBuilder& builder, Color color)
         builder.appendff("rgba({}, {}, {}, 0.{})", color.red(), color.green(), color.blue(), format_to_8bit_compatible(color.alpha()).data());
 }
 
+// https://drafts.csswg.org/cssom/#serialize-a-css-value
+void serialize_a_number(StringBuilder& builder, double value)
+{
+    // -> <number>
+    // A base-ten number using digits 0-9 (U+0030 to U+0039) in the shortest form possible, using "." to separate
+    // decimals (if any), rounding the value if necessary to not produce more than 6 decimals, preceded by "-" (U+002D)
+    // if it is negative.
+    builder.appendff("{:.6}", value);
+}
+
 String serialize_an_identifier(StringView ident)
 {
     StringBuilder builder;
     serialize_an_identifier(builder, ident);
-    return MUST(builder.to_string());
+    return builder.to_string_without_validation();
 }
 
 String serialize_a_string(StringView string)
 {
     StringBuilder builder;
     serialize_a_string(builder, string);
-    return MUST(builder.to_string());
+    return builder.to_string_without_validation();
 }
 
 String serialize_a_url(StringView url)
 {
     StringBuilder builder;
     serialize_a_url(builder, url);
-    return MUST(builder.to_string());
+    return builder.to_string_without_validation();
 }
 
 String serialize_a_srgb_value(Color color)
 {
     StringBuilder builder;
     serialize_a_srgb_value(builder, color);
-    return MUST(builder.to_string());
+    return builder.to_string_without_validation();
+}
+
+String serialize_a_number(double value)
+{
+    StringBuilder builder;
+    serialize_a_number(builder, value);
+    return builder.to_string_without_validation();
 }
 
 // https://drafts.csswg.org/cssom/#serialize-a-css-declaration
@@ -239,7 +256,7 @@ String serialize_a_css_declaration(StringView property, StringView value, Import
     builder.append(';');
 
     // 7. Return s.
-    return MUST(builder.to_string());
+    return builder.to_string_without_validation();
 }
 
 // https://drafts.csswg.org/css-syntax/#serialization
diff --git a/Libraries/LibWeb/CSS/Serialize.h b/Libraries/LibWeb/CSS/Serialize.h
index ec8050686a8..56c52900574 100644
--- a/Libraries/LibWeb/CSS/Serialize.h
+++ b/Libraries/LibWeb/CSS/Serialize.h
@@ -23,11 +23,13 @@ void serialize_a_string(StringBuilder&, StringView string);
 void serialize_a_url(StringBuilder&, StringView url);
 void serialize_unicode_ranges(StringBuilder&, Vector<Gfx::UnicodeRange> const& unicode_ranges);
 void serialize_a_srgb_value(StringBuilder&, Color color);
+void serialize_a_number(StringBuilder&, double value);
 
 String serialize_an_identifier(StringView ident);
 String serialize_a_string(StringView string);
 String serialize_a_url(StringView url);
 String serialize_a_srgb_value(Color color);
+String serialize_a_number(double value);
 
 // https://www.w3.org/TR/cssom/#serialize-a-comma-separated-list
 template<typename T, typename SerializeItem>
diff --git a/Libraries/LibWeb/CSS/StyleValues/NumberStyleValue.cpp b/Libraries/LibWeb/CSS/StyleValues/NumberStyleValue.cpp
index 5e8d106bd98..53689cf87c2 100644
--- a/Libraries/LibWeb/CSS/StyleValues/NumberStyleValue.cpp
+++ b/Libraries/LibWeb/CSS/StyleValues/NumberStyleValue.cpp
@@ -9,18 +9,13 @@
 
 #include "NumberStyleValue.h"
 #include <LibWeb/CSS/Parser/ComponentValue.h>
+#include <LibWeb/CSS/Serialize.h>
 
 namespace Web::CSS {
 
 String NumberStyleValue::to_string(SerializationMode) const
 {
-    // FIXME: This should be moved into Serialize.cpp and used by applicable dimensions as well.
-    // https://drafts.csswg.org/cssom/#serialize-a-css-value
-    // <number>
-    // A base-ten number using digits 0-9 (U+0030 to U+0039) in the shortest form possible, using "." to separate
-    // decimals (if any), rounding the value if necessary to not produce more than 6 decimals, preceded by "-" (U+002D)
-    // if it is negative.
-    return MUST(String::formatted("{:.6}", m_value));
+    return serialize_a_number(m_value);
 }
 
 Vector<Parser::ComponentValue> NumberStyleValue::tokenize() const
diff --git a/Libraries/LibWeb/CSS/StyleValues/TransformationStyleValue.cpp b/Libraries/LibWeb/CSS/StyleValues/TransformationStyleValue.cpp
index a761c8b04ef..6327295fb7d 100644
--- a/Libraries/LibWeb/CSS/StyleValues/TransformationStyleValue.cpp
+++ b/Libraries/LibWeb/CSS/StyleValues/TransformationStyleValue.cpp
@@ -10,6 +10,7 @@
 
 #include "TransformationStyleValue.h"
 #include <AK/StringBuilder.h>
+#include <LibWeb/CSS/Serialize.h>
 #include <LibWeb/CSS/StyleValues/AngleStyleValue.h>
 #include <LibWeb/CSS/StyleValues/LengthStyleValue.h>
 #include <LibWeb/CSS/StyleValues/NumberStyleValue.h>
@@ -138,7 +139,7 @@ String TransformationStyleValue::to_string(SerializationMode mode) const
             if (!raw_value.has_value())
                 return value.to_string(mode);
 
-            return MUST(String::formatted("{:.6}", *raw_value));
+            return serialize_a_number(*raw_value);
         };
 
         auto x_value = resolve_to_string(m_properties.values[0]);