diff --git a/util/sst_dump_tool.cc b/util/sst_dump_tool.cc
index af7ea5977..bd074ea23 100644
--- a/util/sst_dump_tool.cc
+++ b/util/sst_dump_tool.cc
@@ -12,6 +12,7 @@
 #endif
 
 #include <inttypes.h>
+#include "port/port.h"
 
 namespace rocksdb {
 
@@ -166,7 +167,7 @@ int SstFileReader::ShowAllCompressionSizes(size_t block_size) {
   compress_type.insert(std::make_pair(CompressionType::kZSTDNotFinalCompression,
                                       "kZSTDNotFinalCompression"));
 
-  fprintf(stdout, "Block Size: %lu\n", block_size);
+  fprintf(stdout, "Block Size: %" ROCKSDB_PRIszt "\n", block_size);
 
   for (CompressionType i = CompressionType::kNoCompression;
        i <= CompressionType::kZSTDNotFinalCompression;