diff --git a/panel-plugin/utils.c b/panel-plugin/utils.c
index 30647af..922bfe6 100644
--- a/panel-plugin/utils.c
+++ b/panel-plugin/utils.c
@@ -97,7 +97,7 @@ char* format_byte_humanreadable(char* string, int stringsize, double number, int
     }
 
     /* calculate number and appropriate unit size for display */
-    while(number_displayed >= 1024.0 && uidx < sizeof(unit_names))
+    while(number_displayed >= 1024.0 && uidx < G_N_ELEMENTS(unit_names))
     {
         number_displayed /= 1024.0;
         uidx++;