diff --git a/cmd/config.go b/cmd/config.go
index de11ee1..d01f8f9 100644
--- a/cmd/config.go
+++ b/cmd/config.go
@@ -598,7 +598,7 @@ func parseRetentionGridIntervalString(e string) (intervals []RetentionInterval,
 	case "w":
 		durationUnit = 24 * 7 * time.Hour
 	case "mon":
-		durationUnit = 32 * 24 * 7 * time.Hour
+		durationUnit = 24 * 32 * time.Hour
 	default:
 		err = fmt.Errorf("contains unknown time unit '%s'", comps[3])
 		return nil, err