diff --git a/modules/juce_audio_formats/format/juce_AudioFormatWriter.cpp b/modules/juce_audio_formats/format/juce_AudioFormatWriter.cpp
index 0c5edccee6..065f36afa4 100644
--- a/modules/juce_audio_formats/format/juce_AudioFormatWriter.cpp
+++ b/modules/juce_audio_formats/format/juce_AudioFormatWriter.cpp
@@ -276,7 +276,7 @@ public:
 
         if (samplesPerFlush > 0)
         {
-            flushSampleCounter -= numToDo;
+            flushSampleCounter -= size1 + size2;
 
             if (flushSampleCounter <= 0)
             {