diff --git a/src/Std/Time/Format/Basic.lean b/src/Std/Time/Format/Basic.lean
index 88b62af53dd4..f6c16e349d11 100644
--- a/src/Std/Time/Format/Basic.lean
+++ b/src/Std/Time/Format/Basic.lean
@@ -914,9 +914,9 @@ private def dateFromModifier (date : DateTime tz) : TypeFormat modifier :=
   | .H _ => date.hour
   | .m _ => date.minute
   | .s _ => date.date.get.time.second
-  | .S _ => date.nanoseconds
+  | .S _ => date.nanosecond
   | .A _ => date.date.get.time.toMilliseconds
-  | .n _ => date.nanoseconds
+  | .n _ => date.nanosecond
   | .N _ => date.date.get.time.toNanoseconds
   | .V => tz.name
   | .z .short => tz.abbreviation