diff --git a/src/formatters.rs b/src/formatters.rs
index 08bebd7e..e4989731 100644
--- a/src/formatters.rs
+++ b/src/formatters.rs
@@ -143,7 +143,7 @@ pub fn v2s_f32_hz_then_khz_with_note_name(
 ) -> Arc<dyn Fn(f32) -> String + Send + Sync> {
     Arc::new(move |value| {
         // This is the inverse of the formula in `f32_midi_note_to_freq`
-        let fractional_note = ((value / 440.0).log2() * 12.0) + 69.0;
+        let fractional_note = util::freq_to_midi_note(value);
         let note = fractional_note.round();
         let cents = ((fractional_note - note) * 100.0) as i32;
 
diff --git a/src/util.rs b/src/util.rs
index 173464a8..8e5c772e 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -57,6 +57,13 @@ pub fn f32_midi_note_to_freq(note: f32) -> f32 {
     2.0f32.powf((note - 69.0) / 12.0) * 440.0
 }
 
+/// The inverse of [`f32_midi_note_to_freq()`]. This returns a fractional note number. Round to a
+/// whole number, subtract that from the result, and multiply the fractional part by 100 to get the
+/// number of cents.
+pub fn freq_to_midi_note(freq: f32) -> f32 {
+    ((freq / 440.0).log2() * 12.0) + 69.0
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;