diff --git a/test/benchmark-sizes.c b/test/benchmark-sizes.c
index c6044f45..7c6cb1fd 100644
--- a/test/benchmark-sizes.c
+++ b/test/benchmark-sizes.c
@@ -24,14 +24,14 @@
 
 
 BENCHMARK_IMPL(sizes) {
-  LOGF("uv_req_t: %lu bytes\n", sizeof(uv_req_t));
-  LOGF("uv_tcp_t: %lu bytes\n", sizeof(uv_tcp_t));
-  LOGF("uv_prepare_t: %lu bytes\n", sizeof(uv_prepare_t));
-  LOGF("uv_check_t: %lu bytes\n", sizeof(uv_check_t));
-  LOGF("uv_idle_t: %lu bytes\n", sizeof(uv_idle_t));
-  LOGF("uv_async_t: %lu bytes\n", sizeof(uv_async_t));
-  LOGF("uv_timer_t: %lu bytes\n", sizeof(uv_timer_t));
-  LOGF("uv_ares_task_t: %lu bytes\n", sizeof(uv_ares_task_t));
-  LOGF("uv_ares_action_t: %lu bytes\n", sizeof(uv_ares_action_t));
+  LOGF("uv_req_t: %u bytes\n", (unsigned int) sizeof(uv_req_t));
+  LOGF("uv_tcp_t: %u bytes\n", (unsigned int) sizeof(uv_tcp_t));
+  LOGF("uv_prepare_t: %u bytes\n", (unsigned int) sizeof(uv_prepare_t));
+  LOGF("uv_check_t: %u bytes\n", (unsigned int) sizeof(uv_check_t));
+  LOGF("uv_idle_t: %u bytes\n", (unsigned int) sizeof(uv_idle_t));
+  LOGF("uv_async_t: %u bytes\n", (unsigned int) sizeof(uv_async_t));
+  LOGF("uv_timer_t: %u bytes\n", (unsigned int) sizeof(uv_timer_t));
+  LOGF("uv_ares_task_t: %u bytes\n", (unsigned int) sizeof(uv_ares_task_t));
+  LOGF("uv_ares_action_t: %u bytes\n", (unsigned int) sizeof(uv_ares_action_t));
   return 0;
 }