diff --git a/Data/Hourglass/Internal/Win.hs b/Data/Hourglass/Internal/Win.hs
--- a/Data/Hourglass/Internal/Win.hs
+++ b/Data/Hourglass/Internal/Win.hs
@@ -48,14 +48,16 @@
   where toDateTime (SYSTEMTIME wY wM _ wD wH wMin wS _) =
             DateTime (Date (fi wY) (toEnum $ fi $ wM - 1) (fi wD))
                      (TimeOfDay (fi wH) (fi wMin) (fi wS) ns)
-        fi = fromIntegral
+        fi :: (Integral a, Num b) => a -> b
+        fi x = fromIntegral x
 
 dateTimeFromUnixEpoch :: Elapsed -> DateTime
 dateTimeFromUnixEpoch e = toDateTime $ callSystemTime e
   where toDateTime (SYSTEMTIME wY wM _ wD wH wMin wS _) =
             DateTime (Date (fi wY) (toEnum $ fi $ wM - 1) (fi wD))
                      (TimeOfDay (fi wH) (fi wMin) (fi wS) 0)
-        fi = fromIntegral
+        fi :: (Integral a, Num b) => a -> b
+        fi x = fromIntegral x
 
 systemGetTimezone :: IO TimezoneOffset
 systemGetTimezone = do
diff --git a/hourglass.cabal b/hourglass.cabal
--- a/hourglass.cabal
+++ b/hourglass.cabal
@@ -1,5 +1,5 @@
 Name:                hourglass
-Version:             0.2.4
+Version:             0.2.5
 Synopsis:            simple performant time related library
 Description:
     Simple time library focusing on simple but powerful and performant API