diff --git a/pw_kvs/flash_partition_with_stats.cc b/pw_kvs/flash_partition_with_stats.cc
index f966756..7c9531d 100644
--- a/pw_kvs/flash_partition_with_stats.cc
+++ b/pw_kvs/flash_partition_with_stats.cc
@@ -54,7 +54,7 @@
   std::fprintf(out_file,
                ",%zu,%u,%zu",
                utilization_percentage,
-               kvs.transaction_count(),
+               unsigned(kvs.transaction_count()),
                kvs.size());
 
   for (size_t counter : sector_erase_counters()) {