diff --git a/thirdparty/FastHash.h b/thirdparty/FastHash.h
index 86a6be7..8902f21 100644
--- a/thirdparty/FastHash.h
+++ b/thirdparty/FastHash.h
@@ -38,6 +38,7 @@
 // Changes: General uplift and providing a general constant hash for ranges
 
 #include <cstdint>
+#include <cstddef>
 
 #pragma once