diff --git a/src/StretchCalculator.h b/src/StretchCalculator.h
index 56c7de7..c0ab595 100644
--- a/src/StretchCalculator.h
+++ b/src/StretchCalculator.h
@@ -28,6 +28,7 @@
 
 #include <vector>
 #include <map>
+#include <cstdint>
 
 namespace RubberBand
 {