diff --git a/CHANGELOG.md b/CHANGELOG.md
index 05a62d6..a3a4eb8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 ## 0.4.1 (unreleased)
 
+- Improved performance of cosine distance
 - Fixed index scan count
 
 ## 0.4.0 (2023-01-11)
diff --git a/src/vector.c b/src/vector.c
index c287c03..7c0cf4a 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -568,7 +568,7 @@ cosine_distance(PG_FUNCTION_ARGS)
 		normb += bx[i] * bx[i];
 	}
 
-	PG_RETURN_FLOAT8(1 - (distance / (sqrt(norma) * sqrt(normb))));
+	PG_RETURN_FLOAT8(1 - (distance / sqrt(norma * normb)));
 }
 
 /*