diff --git a/src/now.c b/src/now.c
index 36f7e6d..b56d7d7 100644
--- a/src/now.c
+++ b/src/now.c
@@ -30,7 +30,7 @@ int ifnow_now_send(ifnow_now_cfg_t *now_cfg, uint8_t *buf, uint16_t len) {
   memcpy(&packet.wlan.sa, buf + 6, 6);
   memcpy(&packet.wlan.bssid, buf, 6);
 
-  printf("NOW: sending %d bytes\n", sizeof(packet));
+  printf("NOW: sending %ld bytes\n", sizeof(packet));
 
   for(uint16_t i = 0; i < sizeof(packet); i++) {
     printf("%02X ", ((uint8_t*)&packet)[i]);