diff --git a/libraries/DataFlash/examples/DataFlash_test/DataFlash_test.cpp b/libraries/DataFlash/examples/DataFlash_test/DataFlash_test.cpp
index 691b178022..6bdec5b3dc 100644
--- a/libraries/DataFlash/examples/DataFlash_test/DataFlash_test.cpp
+++ b/libraries/DataFlash/examples/DataFlash_test/DataFlash_test.cpp
@@ -68,7 +68,7 @@ static uint16_t log_num;
 
 void setup()
 {
-    DataFlash.Init(log_structure, sizeof(log_structure)/sizeof(log_structure[0]));
+    DataFlash.Init(log_structure, ARRAY_SIZE(log_structure));
 
     hal.console->println("Dataflash Log Test 1.0");