diff --git a/Tools/Replay/LR_MsgHandler.cpp b/Tools/Replay/LR_MsgHandler.cpp
index b0a04bbb19..af5330f215 100644
--- a/Tools/Replay/LR_MsgHandler.cpp
+++ b/Tools/Replay/LR_MsgHandler.cpp
@@ -338,7 +338,7 @@ bool LR_MsgHandler::set_parameter(const char *name, float value)
     const char *ignore_parms[] = { "GPS_TYPE", "AHRS_EKF_USE", 
                                    "COMPASS_ORIENT", "COMPASS_ORIENT2",
                                    "COMPASS_ORIENT3"};
-    for (uint8_t i=0; i<sizeof(ignore_parms)/sizeof(ignore_parms[0]); i++) {
+    for (uint8_t i=0; i < ARRAY_SIZE(ignore_parms); i++) {
         if (strncmp(name, ignore_parms[i], AP_MAX_NAME_SIZE) == 0) {
             ::printf("Ignoring set of %s to %f\n", name, value);
             return true;
diff --git a/Tools/Replay/Replay.cpp b/Tools/Replay/Replay.cpp
index 5ed0b02201..67b10174e8 100644
--- a/Tools/Replay/Replay.cpp
+++ b/Tools/Replay/Replay.cpp
@@ -225,7 +225,7 @@ private:
     SITL sitl;
 #endif
 
-    LogReader logreader{_vehicle.ahrs, _vehicle.ins, _vehicle.barometer, _vehicle.compass, _vehicle.gps, _vehicle.airspeed, _vehicle.dataflash, log_structure, sizeof(log_structure)/sizeof(log_structure[0])};
+    LogReader logreader{_vehicle.ahrs, _vehicle.ins, _vehicle.barometer, _vehicle.compass, _vehicle.gps, _vehicle.airspeed, _vehicle.dataflash, log_structure, ARRAY_SIZE(log_structure)};
 
     FILE *plotf;
     FILE *plotf2;
@@ -357,7 +357,7 @@ void Replay::_parse_command_line(uint8_t argc, char * const argv[])
             strncpy(user_parameters[num_user_parameters].name, gopt.optarg, eq-gopt.optarg);
             user_parameters[num_user_parameters].value = atof(eq+1);
             num_user_parameters++;
-            if (num_user_parameters >= sizeof(user_parameters)/sizeof(user_parameters[0])) {
+            if (num_user_parameters >= ARRAY_SIZE(user_parameters)) {
                 ::printf("Too many user parameters\n");
                 exit(1);
             }