diff --git a/lisp/org/org.el b/lisp/org/org.el
index 02a7a0c..abb2269 100644
--- a/lisp/org/org.el
+++ b/lisp/org/org.el
@@ -17250,11 +17250,11 @@ org-closest-date
 		     (- cday (1+ (floor (/ missing-hours 24)))))
 		n2 (+ cday (floor (/ (- dn missing-hours) 24))))))
        ((eq dw 'day)
-	(setq n1 (+ sday (* dn (floor (/ (- cday sday) dn))))
+	(setq n1 (+ sday (* dn (floor (if (= dn 0) 0 (/ (- cday sday) dn)))))
 	      n2 (+ n1 dn)))
        ((eq dw 'year)
 	(setq d (nth 1 start) m (car start) y1 (nth 2 start) y2 (nth 2 current))
-	(setq y1 (+ (* (floor (/ (- y2 y1) dn)) dn) y1))
+	(setq y1 (+ (* (floor (if (= dn 0) 0 (/ (- y2 y1) dn))) dn) y1))
 	(setq date1 (list m d y1)
 	      n1 (calendar-absolute-from-gregorian date1)
 	      date2 (list m d (+ y1 (* (if (< n1 cday) 1 -1) dn)))