diff --git a/src/openrct2/ReplayManager.cpp b/src/openrct2/ReplayManager.cpp
index 33658c3111..a6adaf02ad 100644
--- a/src/openrct2/ReplayManager.cpp
+++ b/src/openrct2/ReplayManager.cpp
@@ -299,7 +299,7 @@ namespace OpenRCT2
 
             const auto& stream = recSerialiser.GetStream();
             size_t streamLength = stream.GetLength();
-            size_t compressLength = compressBound(streamLength);
+            unsigned long compressLength = compressBound(streamLength);
 
             MemoryStream data(compressLength);