diff --git a/lib/Internal/Utils.hs b/lib/Internal/Utils.hs
index 618f348..d53a9e4 100644
--- a/lib/Internal/Utils.hs
+++ b/lib/Internal/Utils.hs
@@ -66,7 +66,7 @@ compareDate (In md offset) x = case fromMatchYMD md of
     (y, m, _) = toGregorian x
     compareRange start z
       | z < start = LT
-      | otherwise = if (start + fromIntegral offset) < z then GT else EQ
+      | otherwise = if (start + fromIntegral offset - 1) < z then GT else EQ
     toMonth year month = (year * 12) + fromIntegral month
 
 dateMatches :: MatchDate -> Day -> Bool