diff --git a/src/cal-day.scm b/src/cal-day.scm
index bc6894d..d7fdcd2 100644
--- a/src/cal-day.scm
+++ b/src/cal-day.scm
@@ -136,6 +136,12 @@
 	 (apply make-cal-day (map string->number l))
 	 #f)))
 
+ ;; Parses given string as either day or month
+ (define (parse-cal-day/month s)
+   (let ((d (string->cal-day s)))
+     (or d
+	 (string->cal-month s))))
+
  ;; Module self-tests
  (define (cal-day-tests!)
    (run-tests
@@ -172,6 +178,8 @@
     (test-equal? string->cal-day
 		 (string->cal-day "2023-05-11")
 		 (make-cal-day 2023 5 11))
+    (test-true parse-cal-day/month
+	       (cal-day? (parse-cal-day/month "2023-05-11")))
     ))
 
  )