diff --git a/rational.go b/rational.go
index 3d04bbf..ef6cf8f 100644
--- a/rational.go
+++ b/rational.go
@@ -37,7 +37,7 @@ func (r *Rational) SetDen(den int) {
 	r.c.den = C.int(den)
 }
 
-func (r Rational) ToDouble() float64 {
+func (r Rational) Float64() float64 {
 	if r.Num() == 0 || r.Den() == 0 {
 		return 0
 	}
diff --git a/rational_test.go b/rational_test.go
index 9ea4ad9..79fc2b5 100644
--- a/rational_test.go
+++ b/rational_test.go
@@ -16,8 +16,8 @@ func TestRational(t *testing.T) {
 	require.Equal(t, 1, r.Num())
 	require.Equal(t, 2, r.Den())
 	require.Equal(t, "1/2", r.String())
-	require.Equal(t, 0.5, r.ToDouble())
+	require.Equal(t, 0.5, r.Float64())
 	r.SetDen(0)
-	require.Equal(t, float64(0), r.ToDouble())
+	require.Equal(t, float64(0), r.Float64())
 	require.Equal(t, "0", r.String())
 }