diff --git a/src/naive/naive_vec4.h b/src/naive/naive_vec4.h
index 1e37c52..8b53440 100644
--- a/src/naive/naive_vec4.h
+++ b/src/naive/naive_vec4.h
@@ -74,6 +74,11 @@ private:
 	return std::sqrt(dot3(v, v));
 }
 
+[[nodiscard]] inline float magnitude3_sq(vec4 v) noexcept
+{
+	return dot3(v, v);
+}
+
 [[nodiscard]] inline vec4 norm3(vec4 v) noexcept
 {
 	const float inv = 1.0f / magnitude3(v);   // normalize xyz, keep w
diff --git a/src/tests/naive_tests.cpp b/src/tests/naive_tests.cpp
index 8378006..26caae5 100644
--- a/src/tests/naive_tests.cpp
+++ b/src/tests/naive_tests.cpp
@@ -123,6 +123,24 @@ TEST(naive_vec4, magnitude_b)
 	EXPECT_FLOAT_EQ(check, result);
 }
 
+TEST(naive_vec4, magnitude3_sq_a)
+{
+	vec4 a = { 1.0f, 0.0f, 0.0f, 0.0f };
+	float check = 1.0f;
+	float result = magnitude3_sq(a);
+
+	EXPECT_FLOAT_EQ(check, result);
+}
+
+TEST(naive_vec4, magnitude3_sq_b)
+{
+	vec4 a = { 1.0f, 0.0f, 1.0f, 1.0f };
+	float check = 2.0f;
+	float result = magnitude3_sq(a);
+
+	EXPECT_FLOAT_EQ(check, result);
+}
+
 TEST(naive_vec4, expression_a)
 {
 	vec4 a = { 1.0f, 1.0f, 1.0f, 1.0f };
diff --git a/src/tests/vec4_tests.cpp b/src/tests/vec4_tests.cpp
index 98f83a8..6b1b8b7 100644
--- a/src/tests/vec4_tests.cpp
+++ b/src/tests/vec4_tests.cpp
@@ -121,6 +121,24 @@ TEST(vec4, magnitude_b)
 	EXPECT_FLOAT_EQ(check, result);
 }
 
+TEST(vec4, magnitude3_sq_a)
+{
+	vec4 a = { 1.0f, 0.0f, 0.0f, 0.0f };
+	float check = 1.0f;
+	float result = magnitude3_sq(a);
+
+	EXPECT_FLOAT_EQ(check, result);
+}
+
+TEST(vec4, magnitude3_sq_b)
+{
+	vec4 a = { 1.0f, 0.0f, 1.0f, 1.0f };
+	float check = 2.0f;
+	float result = magnitude3_sq(a);
+
+	EXPECT_FLOAT_EQ(check, result);
+}
+
 TEST(vec4, expression_a)
 {
 	vec4 a = { 1.0f, 1.0f, 1.0f, 1.0f };