diff --git a/src/Cron.hs b/src/Cron.hs
index 0b28fa81f..c37267249 100644
--- a/src/Cron.hs
+++ b/src/Cron.hs
@@ -117,40 +117,41 @@ listToMatch :: [a] -> CronNextMatch a
 listToMatch [] = MatchNone
 listToMatch (t:_) = MatchAt t
 
-genMatch ::  Int -- ^ Period
+genMatch :: Int -- ^ Period
+         -> Bool -- ^ Modular
          -> Natural -- ^ Start value
          -> CronMatch
          -> [Natural]
-genMatch p st CronMatchAny = take p [st..]
-genMatch _ _ CronMatchNone = []
-genMatch p _ (CronMatchSome set) = take p . Set.toAscList $ toNullable set
-genMatch p st (CronMatchStep step) = do
+genMatch p m st CronMatchAny = take p $ map (bool id (succ . (`mod` fromIntegral p)) m) [st..]
+genMatch _ _ _ CronMatchNone = []
+genMatch p m _ (CronMatchSome set) = take p . map (bool id (succ . (`mod` fromIntegral p)) m) . Set.toAscList $ toNullable set
+genMatch p m st (CronMatchStep step) = do
   start <- [st..st + step]
   guard $ (start `mod` step) == 0
-  take (ceiling $ fromIntegral p % step) [start,start + step..]
-genMatch p st (CronMatchContiguous from to) = take p $ [max st from..to]
-genMatch _ _ (CronMatchIntersect CronMatchNone _) = []
-genMatch _ _ (CronMatchIntersect _ CronMatchNone) = []
-genMatch p st (CronMatchIntersect CronMatchAny other) = genMatch p st other
-genMatch p st (CronMatchIntersect other CronMatchAny) = genMatch p st other
-genMatch p st (CronMatchIntersect (CronMatchStep st1) (CronMatchStep st2))
-  = genMatch p st . CronMatchStep $ lcm st1 st2
-genMatch p st (CronMatchIntersect aGen bGen)
+  take (ceiling $ fromIntegral p % step) $ map (bool id (succ . (`mod` fromIntegral p)) m) [start,start + step..]
+genMatch p m st (CronMatchContiguous from to) = take p . map (bool id (succ . (`mod` fromIntegral p)) m) $ [max st from..to]
+genMatch _ _ _ (CronMatchIntersect CronMatchNone _) = []
+genMatch _ _ _ (CronMatchIntersect _ CronMatchNone) = []
+genMatch p m st (CronMatchIntersect CronMatchAny other) = genMatch p m st other
+genMatch p m st (CronMatchIntersect other CronMatchAny) = genMatch p m st other
+genMatch p m st (CronMatchIntersect (CronMatchStep st1) (CronMatchStep st2))
+  = genMatch p m st . CronMatchStep $ lcm st1 st2
+genMatch p m st (CronMatchIntersect aGen bGen)
   | [] <- as' = []
-  | (a:as) <- as' = mergeAnd (a:as) (genMatch p a bGen)
+  | (a:as) <- as' = mergeAnd (a:as) (genMatch p m a bGen)
   where
-    as' = genMatch p st aGen
+    as' = genMatch p m st aGen
     mergeAnd [] _ = []
     mergeAnd _ [] = []
     mergeAnd (a:as) (b:bs)
       | a <  b = mergeAnd as (b:bs)
       | a == b = a : mergeAnd as bs
       | a >  b = mergeAnd (a:as) bs
-genMatch p st (CronMatchUnion CronMatchNone other) = genMatch p st other
-genMatch p st (CronMatchUnion other CronMatchNone) = genMatch p st other
-genMatch p st (CronMatchUnion CronMatchAny _) = genMatch p st CronMatchAny
-genMatch p st (CronMatchUnion _ CronMatchAny) = genMatch p st CronMatchAny
-genMatch p st (CronMatchUnion aGen bGen) = merge (genMatch p st aGen) (genMatch p st bGen)
+genMatch p m st (CronMatchUnion CronMatchNone other) = genMatch p m st other
+genMatch p m st (CronMatchUnion other CronMatchNone) = genMatch p m st other
+genMatch p m st (CronMatchUnion CronMatchAny _) = genMatch p m st CronMatchAny
+genMatch p m st (CronMatchUnion _ CronMatchAny) = genMatch p m st CronMatchAny
+genMatch p m st (CronMatchUnion aGen bGen) = merge (genMatch p m st aGen) (genMatch p m st bGen)
   where
     merge [] bs = bs
     merge as [] = as
@@ -188,16 +189,16 @@ nextCronMatch tz mPrev now c@Cron{..}
         | otherwise -> MatchNone
       CronCalendar{..} -> listToMatch $ do
         let CronDate{..} = toCronDate $ utcToLocalTimeTZ tz ref
-        cronYear <- genMatch 400 cdYear cronYear
-        cronWeekOfYear <- genMatch 53 cdWeekOfYear cronWeekOfYear
-        cronDayOfYear <- genMatch 366 cdDayOfYear cronDayOfYear
-        cronMonth <- genMatch 12 cdMonth cronMonth
-        cronWeekOfMonth <- genMatch 5 cdWeekOfMonth cronWeekOfMonth
-        cronDayOfMonth <- genMatch 31 cdDayOfMonth cronDayOfMonth
-        cronDayOfWeek <- genMatch 7 cdDayOfWeek cronDayOfWeek
-        cronHour <- genMatch 24 cdHour cronHour
-        cronMinute <- genMatch 60 cdMinute cronMinute
-        cronSecond <- genMatch 60 cdSecond cronSecond
+        cronYear <- genMatch 400 False cdYear cronYear
+        cronWeekOfYear <- genMatch 53 True cdWeekOfYear cronWeekOfYear
+        cronDayOfYear <- genMatch 366 True cdDayOfYear cronDayOfYear
+        cronMonth <- genMatch 12 True cdMonth cronMonth
+        cronWeekOfMonth <- genMatch 5 True cdWeekOfMonth cronWeekOfMonth
+        cronDayOfMonth <- genMatch 31 True cdDayOfMonth cronDayOfMonth
+        cronDayOfWeek <- genMatch 7 True cdDayOfWeek cronDayOfWeek
+        cronHour <- genMatch 24 True cdHour cronHour
+        cronMinute <- genMatch 60 True cdMinute cronMinute
+        cronSecond <- genMatch 60 True cdSecond cronSecond
         guard $ consistentCronDate CronDate{..}
         localDay <- maybeToList $ fromGregorianValid (fromIntegral cronYear) (fromIntegral cronMonth) (fromIntegral cronDayOfMonth)
         let localTimeOfDay = TimeOfDay (fromIntegral cronHour) (fromIntegral cronMinute) (fromIntegral cronSecond)