diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index c93ef33b01d3..eea700723976 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -70,7 +70,7 @@ static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
 		time64_t time = rtc_tm_to_time64(tm);
 		time64_t range_min = rtc->set_start_time ? rtc->start_secs :
 			rtc->range_min;
-		time64_t range_max = rtc->set_start_time ?
+		timeu64_t range_max = rtc->set_start_time ?
 			(rtc->start_secs + rtc->range_max - rtc->range_min) :
 			rtc->range_max;