diff --git a/Libraries/LibJS/Runtime/GlobalObject.cpp b/Libraries/LibJS/Runtime/GlobalObject.cpp
index a0f30666296..0612da4669e 100644
--- a/Libraries/LibJS/Runtime/GlobalObject.cpp
+++ b/Libraries/LibJS/Runtime/GlobalObject.cpp
@@ -144,8 +144,7 @@ Value GlobalObject::is_nan(Interpreter& interpreter)
 
 Value GlobalObject::is_finite(Interpreter& interpreter)
 {
-    auto value = interpreter.argument(0).to_number();
-    return Value(!value.is_infinity() && !value.is_nan());
+    return Value(interpreter.argument(0).to_number().is_finite_number());
 }
 
 }
diff --git a/Libraries/LibJS/Runtime/NumberConstructor.cpp b/Libraries/LibJS/Runtime/NumberConstructor.cpp
index 1713253d0c1..d1e2d8b245b 100644
--- a/Libraries/LibJS/Runtime/NumberConstructor.cpp
+++ b/Libraries/LibJS/Runtime/NumberConstructor.cpp
@@ -40,6 +40,7 @@ namespace JS {
 NumberConstructor::NumberConstructor()
     : NativeFunction("Number", *interpreter().global_object().function_prototype())
 {
+    put_native_function("isFinite", is_finite, 1);
     put_native_function("isSafeInteger", is_safe_integer, 1);
 
     put("prototype", interpreter().global_object().number_prototype());
@@ -73,6 +74,11 @@ Value NumberConstructor::construct(Interpreter& interpreter)
     return NumberObject::create(interpreter.global_object(), number);
 }
 
+Value NumberConstructor::is_finite(Interpreter& interpreter)
+{
+    return Value(interpreter.argument(0).is_finite_number());
+}
+
 Value NumberConstructor::is_safe_integer(Interpreter& interpreter)
 {
     if (!interpreter.argument(0).is_number())
diff --git a/Libraries/LibJS/Runtime/NumberConstructor.h b/Libraries/LibJS/Runtime/NumberConstructor.h
index 34d7b5d4ed5..23557009b05 100644
--- a/Libraries/LibJS/Runtime/NumberConstructor.h
+++ b/Libraries/LibJS/Runtime/NumberConstructor.h
@@ -42,6 +42,7 @@ private:
     virtual bool has_constructor() const override { return true; }
     virtual const char* class_name() const override { return "NumberConstructor"; }
 
+    static Value is_finite(Interpreter&);
     static Value is_safe_integer(Interpreter&);
 };
 
diff --git a/Libraries/LibJS/Tests/Number.isFinite.js b/Libraries/LibJS/Tests/Number.isFinite.js
new file mode 100644
index 00000000000..09ae0cd9ec8
--- /dev/null
+++ b/Libraries/LibJS/Tests/Number.isFinite.js
@@ -0,0 +1,29 @@
+load("test-common.js");
+
+try {
+    assert(Number.isFinite.length === 1);
+
+    assert(Number.isFinite(0) === true);
+    assert(Number.isFinite(1.23) === true);
+    assert(Number.isFinite(42) === true);
+
+    assert(Number.isFinite("") === false);
+    assert(Number.isFinite("0") === false);
+    assert(Number.isFinite("42") === false);
+    assert(Number.isFinite(true) === false);
+    assert(Number.isFinite(false) === false);
+    assert(Number.isFinite(null) === false);
+    assert(Number.isFinite([]) === false);
+    assert(Number.isFinite() === false);
+    assert(Number.isFinite(NaN) === false);
+    assert(Number.isFinite(undefined) === false);
+    assert(Number.isFinite(Infinity) === false);
+    assert(Number.isFinite(-Infinity) === false);
+    assert(Number.isFinite("foo") === false);
+    assert(Number.isFinite({}) === false);
+    assert(Number.isFinite([1, 2, 3]) === false);
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e.message);
+}
diff --git a/Libraries/LibJS/Tests/Number.isSafeInteger.js b/Libraries/LibJS/Tests/Number.isSafeInteger.js
index 407b999d9ae..ffa66a1a64b 100644
--- a/Libraries/LibJS/Tests/Number.isSafeInteger.js
+++ b/Libraries/LibJS/Tests/Number.isSafeInteger.js
@@ -2,12 +2,14 @@ load("test-common.js");
 
 try {
     assert(Number.isSafeInteger.length === 1);
+
     assert(Number.isSafeInteger(0) === true);
     assert(Number.isSafeInteger(1) === true);
     assert(Number.isSafeInteger(2.0) === true);
     assert(Number.isSafeInteger(42) === true);
     assert(Number.isSafeInteger(Number.MAX_SAFE_INTEGER) === true);
     assert(Number.isSafeInteger(Number.MIN_SAFE_INTEGER) === true);
+
     assert(Number.isSafeInteger() === false);
     assert(Number.isSafeInteger("1") === false);
     assert(Number.isSafeInteger(2.1) === false);
diff --git a/Libraries/LibJS/Tests/isFinite.js b/Libraries/LibJS/Tests/isFinite.js
index 095cab40180..03d4f3d8b68 100644
--- a/Libraries/LibJS/Tests/isFinite.js
+++ b/Libraries/LibJS/Tests/isFinite.js
@@ -4,6 +4,7 @@ try {
     assert(isFinite.length === 1);
 
     assert(isFinite(0) === true);
+    assert(isFinite(1.23) === true);
     assert(isFinite(42) === true);
     assert(isFinite("") === true);
     assert(isFinite("0") === true);