diff --git a/src/AudioFormat.hxx b/src/AudioFormat.hxx
index 8c9cda3e3..dc2651daf 100644
--- a/src/AudioFormat.hxx
+++ b/src/AudioFormat.hxx
@@ -149,12 +149,6 @@ struct AudioFormat {
 	 */
 	unsigned GetFrameSize() const;
 
-	/**
-	 * Returns the floating point factor which converts a time
-	 * span to a storage size in bytes.
-	 */
-	double GetTimeToSize() const;
-
 	template<typename D>
 	constexpr auto TimeToFrames(D t) const noexcept {
 		using Period = typename D::period;
@@ -236,12 +230,6 @@ AudioFormat::GetFrameSize() const
 	return GetSampleSize() * channels;
 }
 
-inline double
-AudioFormat::GetTimeToSize() const
-{
-	return sample_rate * GetFrameSize();
-}
-
 /**
  * Renders the #AudioFormat object into a string, e.g. for printing
  * it in a log file.