diff --git a/src/Data/Time/TimeSpan.hs b/src/Data/Time/TimeSpan.hs
--- a/src/Data/Time/TimeSpan.hs
+++ b/src/Data/Time/TimeSpan.hs
@@ -1,10 +1,10 @@
 {-# LANGUAGE BangPatterns #-}
 module Data.Time.TimeSpan
   ( TimeSpan
-  , milliseconds, seconds, minutes, hours, days
-  , toMicroseconds, toMilliseconds, toSeconds, toMinutes, toHours, toDays
-  , absTS
-  , diffUTCTimeTS, addUTCTimeTS
+  , milliseconds, seconds, minutes, hours, days, weeks
+  , toMicroseconds, toMilliseconds, toSeconds, toMinutes, toHours, toDays, toWeeks
+  , absTS, multiplyTS
+  , diffUTCTimeTS, addUTCTimeTS, subUTCTimeTS
   , sleepTS, timeoutTS
   , timeAction
   )
@@ -16,11 +16,14 @@
 import System.Timeout
 
 -- | An abstract timespan. Use the provided smart constructors to create
--- a meaningful timespan
+-- a meaningful timespan. Note that on first sight a `Num` instance might
+-- seem desirable, but this would defeat the purpose of having transparent
+-- and explicitly constructed timespans due to `fromInteger`.
 newtype TimeSpan
   = TimeSpan { unTimeSpan :: Double } -- as milliseconds
   deriving (Show, Eq, Ord)
 
+-- | An empty `TimeSpan` is 0, and `mappend` is defined as addition
 instance Monoid TimeSpan where
     mempty = TimeSpan 0
     mappend (TimeSpan a) (TimeSpan b) = TimeSpan (a + b)
@@ -40,6 +43,9 @@
 days :: Double -> TimeSpan
 days = hours . (* 24)
 
+weeks :: Double -> TimeSpan
+weeks = days . (* 7)
+
 toMicroseconds :: TimeSpan -> Double
 toMicroseconds = (* 1000) . toMilliseconds
 
@@ -58,14 +64,23 @@
 toDays :: TimeSpan -> Double
 toDays = (/24) . toHours
 
+toWeeks :: TimeSpan -> Double
+toWeeks = (/7) . toDays
+
 absTS :: TimeSpan -> TimeSpan
 absTS (TimeSpan x) = TimeSpan (abs x)
 
+multiplyTS :: TimeSpan -> Double -> TimeSpan
+multiplyTS (TimeSpan x) fact = TimeSpan (fact * x)
+
 diffUTCTimeTS :: UTCTime -> UTCTime -> TimeSpan
 diffUTCTimeTS a b = seconds $ fromRational $ toRational $ diffUTCTime a b
 
 addUTCTimeTS :: TimeSpan -> UTCTime -> UTCTime
 addUTCTimeTS a = addUTCTime (fromRational $ toRational $ toSeconds a)
+
+subUTCTimeTS :: TimeSpan -> UTCTime -> UTCTime
+subUTCTimeTS a = addUTCTime ((-1) * fromRational (toRational $ toSeconds a))
 
 sleepTS :: TimeSpan -> IO ()
 sleepTS ts = threadDelay (round $ toMicroseconds ts)
diff --git a/timespan.cabal b/timespan.cabal
--- a/timespan.cabal
+++ b/timespan.cabal
@@ -1,5 +1,5 @@
 name:                timespan
-version:             0.2.0.0
+version:             0.3.0.0
 synopsis:            Useful timespan datatype and functions
 description:         A data type for time spans with some useful utility functions
 homepage:            https://github.com/agrafix/timespan#readme