diff --git a/drivers/rtc/proc.c b/drivers/rtc/proc.c
index 73344598fc1b..cbcdbb19d848 100644
--- a/drivers/rtc/proc.c
+++ b/drivers/rtc/proc.c
@@ -23,8 +23,8 @@ static bool is_rtc_hctosys(struct rtc_device *rtc)
 	int size;
 	char name[NAME_SIZE];
 
-	size = scnprintf(name, NAME_SIZE, "rtc%d", rtc->id);
-	if (size > NAME_SIZE)
+	size = snprintf(name, NAME_SIZE, "rtc%d", rtc->id);
+	if (size >= NAME_SIZE)
 		return false;
 
 	return !strncmp(name, CONFIG_RTC_HCTOSYS_DEVICE, NAME_SIZE);