diff --git a/Userland/Libraries/LibWeb/CSS/Angle.cpp b/Userland/Libraries/LibWeb/CSS/Angle.cpp
index 37acc9ad65a..38a56ee51ed 100644
--- a/Userland/Libraries/LibWeb/CSS/Angle.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Angle.cpp
@@ -52,6 +52,11 @@ double Angle::to_degrees() const
     VERIFY_NOT_REACHED();
 }
 
+double Angle::to_radians() const
+{
+    return to_degrees() * (AK::Pi<double> / 180.0);
+}
+
 StringView Angle::unit_name() const
 {
     switch (m_type) {
diff --git a/Userland/Libraries/LibWeb/CSS/Angle.h b/Userland/Libraries/LibWeb/CSS/Angle.h
index e6d1c94459e..b9339909827 100644
--- a/Userland/Libraries/LibWeb/CSS/Angle.h
+++ b/Userland/Libraries/LibWeb/CSS/Angle.h
@@ -28,7 +28,9 @@ public:
     Angle percentage_of(Percentage const&) const;
 
     ErrorOr<String> to_string() const;
+
     double to_degrees() const;
+    double to_radians() const;
 
     Type type() const { return m_type; }
     double raw_value() const { return m_value; }
diff --git a/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
index f86538e2847..fe34bd26283 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -3594,6 +3594,30 @@ ErrorOr<OwnPtr<CalculationNode>> Parser::parse_sign_function(Function const& fun
     return TRY(SignCalculationNode::create(calculation_node.release_nonnull()));
 }
 
+ErrorOr<OwnPtr<CalculationNode>> Parser::parse_sin_function(Function const& function)
+{
+    auto calculation_node = TRY(parse_a_calculation(function.values()));
+
+    if (!calculation_node) {
+        dbgln_if(CSS_PARSER_DEBUG, "sin() parameter must be a valid calculation"sv);
+        return nullptr;
+    }
+
+    auto maybe_parameter_type = calculation_node->resolved_type();
+    if (!maybe_parameter_type.has_value()) {
+        dbgln_if(CSS_PARSER_DEBUG, "Failed to resolve type for sin() parameter"sv);
+        return nullptr;
+    }
+
+    auto resolved_type = maybe_parameter_type.value();
+    if (resolved_type != CalculatedStyleValue::ResolvedType::Number && resolved_type != CalculatedStyleValue::ResolvedType::Angle) {
+        dbgln_if(CSS_PARSER_DEBUG, "sin() parameter must be a number or angle"sv);
+        return nullptr;
+    }
+
+    return TRY(SinCalculationNode::create(calculation_node.release_nonnull()));
+}
+
 ErrorOr<RefPtr<StyleValue>> Parser::parse_dynamic_value(ComponentValue const& component_value)
 {
     if (component_value.is_function()) {
@@ -3638,6 +3662,9 @@ ErrorOr<OwnPtr<CalculationNode>> Parser::parse_a_calc_function_node(Function con
     if (function.name().equals_ignoring_ascii_case("sign"sv))
         return TRY(parse_sign_function(function));
 
+    if (function.name().equals_ignoring_ascii_case("sin"sv))
+        return TRY(parse_sin_function(function));
+
     dbgln_if(CSS_PARSER_DEBUG, "We didn't implement `{}` function yet", function.name());
     return nullptr;
 }
diff --git a/Userland/Libraries/LibWeb/CSS/Parser/Parser.h b/Userland/Libraries/LibWeb/CSS/Parser/Parser.h
index c33ca081f25..2703218cde5 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/Parser.h
+++ b/Userland/Libraries/LibWeb/CSS/Parser/Parser.h
@@ -295,6 +295,7 @@ private:
     ErrorOr<OwnPtr<CalculationNode>> parse_clamp_function(Function const&);
     ErrorOr<OwnPtr<CalculationNode>> parse_abs_function(Function const&);
     ErrorOr<OwnPtr<CalculationNode>> parse_sign_function(Function const&);
+    ErrorOr<OwnPtr<CalculationNode>> parse_sin_function(Function const&);
     ErrorOr<RefPtr<StyleValue>> parse_dimension_value(ComponentValue const&);
     ErrorOr<RefPtr<StyleValue>> parse_integer_value(TokenStream<ComponentValue>&);
     ErrorOr<RefPtr<StyleValue>> parse_number_value(TokenStream<ComponentValue>&);
diff --git a/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.cpp b/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.cpp
index 495cdefdef9..80b7043ed4d 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.cpp
@@ -24,6 +24,14 @@ static bool is_dimension(CalculatedStyleValue::ResolvedType type)
         && type != CalculatedStyleValue::ResolvedType::Percentage;
 }
 
+static double resolve_value_radians(CalculatedStyleValue::CalculationResult::Value value)
+{
+    return value.visit(
+        [](Number const& number) { return number.value(); },
+        [](Angle const& angle) { return angle.to_radians(); },
+        [](auto const&) { VERIFY_NOT_REACHED(); return 0.0; });
+};
+
 static double resolve_value(CalculatedStyleValue::CalculationResult::Value value, Optional<Length::ResolutionContext const&> context)
 {
     return value.visit(
@@ -842,6 +850,60 @@ ErrorOr<void> ConstantCalculationNode::dump(StringBuilder& builder, int indent)
     return {};
 }
 
+ErrorOr<NonnullOwnPtr<SinCalculationNode>> SinCalculationNode::create(NonnullOwnPtr<CalculationNode> value)
+{
+    return adopt_nonnull_own_or_enomem(new (nothrow) SinCalculationNode(move(value)));
+}
+
+SinCalculationNode::SinCalculationNode(NonnullOwnPtr<CalculationNode> value)
+    : CalculationNode(Type::Sin)
+    , m_value(move(value))
+{
+}
+
+SinCalculationNode::~SinCalculationNode() = default;
+
+ErrorOr<String> SinCalculationNode::to_string() const
+{
+    StringBuilder builder;
+    builder.append("sin("sv);
+    builder.append(TRY(m_value->to_string()));
+    builder.append(")"sv);
+    return builder.to_string();
+}
+
+Optional<CalculatedStyleValue::ResolvedType> SinCalculationNode::resolved_type() const
+{
+    return CalculatedStyleValue::ResolvedType::Number;
+}
+
+bool SinCalculationNode::contains_percentage() const
+{
+    return m_value->contains_percentage();
+}
+
+CalculatedStyleValue::CalculationResult SinCalculationNode::resolve(Optional<Length::ResolutionContext const&> context, CalculatedStyleValue::PercentageBasis const& percentage_basis) const
+{
+    auto node_a = m_value->resolve(context, percentage_basis);
+    auto node_a_value = resolve_value_radians(node_a.value());
+    auto result = sin(node_a_value);
+
+    return { Number(Number::Type::Number, result) };
+}
+
+ErrorOr<void> SinCalculationNode::for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const& callback)
+{
+    TRY(m_value->for_each_child_node(callback));
+    TRY(callback(m_value));
+    return {};
+}
+
+ErrorOr<void> SinCalculationNode::dump(StringBuilder& builder, int indent) const
+{
+    TRY(builder.try_appendff("{: >{}}SIN: {}\n", "", indent, TRY(to_string())));
+    return {};
+}
+
 void CalculatedStyleValue::CalculationResult::add(CalculationResult const& other, Optional<Length::ResolutionContext const&> context, PercentageBasis const& percentage_basis)
 {
     add_or_subtract_internal(SumOperation::Add, other, context, percentage_basis);
diff --git a/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h b/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h
index 972d2ee1bd6..483b624fe5d 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h
+++ b/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h
@@ -152,6 +152,16 @@ public:
         // https://drafts.csswg.org/css-values-4/#calc-constants
         Constant,
 
+        // Trigonometric functions, a sub-type of operator node
+        // https://drafts.csswg.org/css-values-4/#trig-funcs
+        Sin,
+        Cos,
+        Tan,
+        Asin,
+        Acos,
+        Atan,
+        Atan2,
+
         // This only exists during parsing.
         Unparsed,
     };
@@ -386,4 +396,22 @@ private:
     CalculationNode::ConstantType m_constant;
 };
 
+class SinCalculationNode final : public CalculationNode {
+public:
+    static ErrorOr<NonnullOwnPtr<SinCalculationNode>> create(NonnullOwnPtr<CalculationNode>);
+    ~SinCalculationNode();
+
+    virtual ErrorOr<String> to_string() const override;
+    virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual bool contains_percentage() const override;
+    virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
+    virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
+
+    virtual ErrorOr<void> dump(StringBuilder&, int indent) const override;
+
+private:
+    SinCalculationNode(NonnullOwnPtr<CalculationNode>);
+    NonnullOwnPtr<CalculationNode> m_value;
+};
+
 }