diff --git a/brmsaptool.scm b/brmsaptool.scm
index 8b4c553..9f7a8d6 100644
--- a/brmsaptool.scm
+++ b/brmsaptool.scm
@@ -127,8 +127,23 @@
        (>= (cadr m 1))
        (<= (cadr m 12))))
 
+;; Converts string in a format YYYY-MM to valid month. Returns #f if
+;; the conversion fails.
 (define (string->month s)
-  (list 2023 1))
+  (let ((l (string-split s "-")))
+    (if (or (not l)
+	    (nil? l)
+	    (nil? (cdr l))
+	    (not (nil? (cddr l))))
+	#f
+	(let ((y (string->number (car l)))
+	      (m (string->number (cadr l))))
+	  (if (and y m)
+	      (let ((M (list y m)))
+		(if (valid-month? M)
+		    M
+		    #f))
+	      #f)))))
 
 ;; Formats (valid) month as YYYY-MM string
 (define (month->string M)
@@ -165,7 +180,10 @@
   (unit-test 'month-valid? (month-valid? '(2023 5)))
   (unit-test 'month-valid?-bad-year (not (month-valid? '(999 8))))
   (unit-test 'month-valid?-bad-month (not (month-valid? '(2023 -5))))
-  ;; Parsing
+  (unit-test 'string->month (equal? (string->month "2023-01" '(2023 1))))
+  (unit-test 'string->month-bad-month (not (string->month "2023-13")))
+  (unit-test 'string->month-nonumber-year (not (string->month "YYYY-01")))
+  (unit-test 'string->month-nonumber-month (not (string->month "2023-MMM")))
   (unit-test 'month->string (equal? (month->string '(2023 1)) "2023-01"))
   (unit-test 'month->string-bad-year (with-handler (lambda (x) #t) (month->string '(999 12)) #f))
   (unit-test 'month->string-bad-month (with-handler (lambda (x) #t) (month->string '(2023 13)) #f))