diff --git a/kernel/printk.c b/kernel/printk.c
index 19c0d7bcf24a..357f714ddd49 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -870,10 +870,11 @@ static size_t print_time(u64 ts, char *buf)
 	if (!printk_time)
 		return 0;
 
-	if (!buf)
-		return 15;
-
 	rem_nsec = do_div(ts, 1000000000);
+
+	if (!buf)
+		return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts);
+
 	return sprintf(buf, "[%5lu.%06lu] ",
 		       (unsigned long)ts, rem_nsec / 1000);
 }