diff --git a/lib/src/tuning/tuning_system.dart b/lib/src/tuning/tuning_system.dart
index f0111d91..de68783e 100644
--- a/lib/src/tuning/tuning_system.dart
+++ b/lib/src/tuning/tuning_system.dart
@@ -57,18 +57,21 @@ class EqualTemperament extends TuningSystem {
   double ratio([int semitones = 1]) =>
       math.pow(2, semitones / octaveDivisions).toDouble();
 
-  /// Returns the number of cents for [semitones] in this [EqualTemperament].
+  /// Returns the number of cents for [ratio] in this [EqualTemperament].
   ///
   /// See [Cent](https://en.wikipedia.org/wiki/Cent_(music)).
   ///
   /// Example:
   /// ```dart
-  /// EqualTemperament.edo12.cents() == 100
-  /// EqualTemperament.edo12.cents(7) == 700
-  /// EqualTemperament.edo19.cents() == 63.16
+  /// var ratio = EqualTemperament.edo12.ratio;
+  /// EqualTemperament.edo12.cents(ratio()) == 100
+  /// EqualTemperament.edo12.cents(ratio(7)) == 700
+  ///
+  /// ratio = EqualTemperament.edo19.ratio;
+  /// EqualTemperament.edo19.cents(ratio()) == 63.16
   /// ```
-  double cents([int semitones = 1]) =>
-      math.log(ratio(semitones)) /
+  double cents(double ratio) =>
+      math.log(ratio) /
       math.log(2) *
       100 *
       EqualTemperament.edo12.octaveDivisions;
@@ -90,6 +93,6 @@ class EqualTemperament extends TuningSystem {
       semitonesUpToP5 += divisionEntry.value;
     }
 
-    return cents(semitonesUpToP5);
+    return cents(ratio(semitonesUpToP5));
   }
 }
diff --git a/test/src/tuning/tuning_system_test.dart b/test/src/tuning/tuning_system_test.dart
index a4367986..014da959 100644
--- a/test/src/tuning/tuning_system_test.dart
+++ b/test/src/tuning/tuning_system_test.dart
@@ -26,16 +26,20 @@ void main() {
 
     group('.cents()', () {
       test(
-        'should return the number of cents for semitones in this '
-        'EqualTemperament',
+        'should return the number of cents for ratio in this EqualTemperament',
         () {
-          expect(EqualTemperament.edo12.cents(), closeTo(100, 0.01));
-          expect(EqualTemperament.edo12.cents(6), closeTo(600, 0.01));
-          expect(EqualTemperament.edo12.cents(12), closeTo(1200, 0.01));
+          var ratio = EqualTemperament.edo12.ratio;
+          expect(EqualTemperament.edo12.cents(ratio()), closeTo(100, 0.01));
+          expect(EqualTemperament.edo12.cents(ratio(6)), closeTo(600, 0.01));
+          expect(EqualTemperament.edo12.cents(ratio(12)), closeTo(1200, 0.01));
 
-          expect(EqualTemperament.edo19.cents(), closeTo(63.16, 0.01));
-          expect(EqualTemperament.edo19.cents(10), closeTo(631.58, 0.01));
-          expect(EqualTemperament.edo19.cents(19), closeTo(1200, 0.01));
+          ratio = EqualTemperament.edo19.ratio;
+          expect(EqualTemperament.edo19.cents(ratio()), closeTo(63.16, 0.01));
+          expect(
+            EqualTemperament.edo19.cents(ratio(10)),
+            closeTo(631.58, 0.01),
+          );
+          expect(EqualTemperament.edo19.cents(ratio(19)), closeTo(1200, 0.01));
         },
       );
     });