diff --git a/Data/ConfigManager.hs b/Data/ConfigManager.hs
--- a/Data/ConfigManager.hs
+++ b/Data/ConfigManager.hs
@@ -22,6 +22,9 @@
   -- ** Comments
   -- $comments
 
+  -- ** Example
+  -- $example
+
   -- * Configuration loading
   readConfig
 
@@ -31,7 +34,6 @@
   ) where
 
 import Prelude hiding (lookup)
-import Text.Read (readMaybe)
 
 import Data.Text (Text)
 import qualified Data.Text as T
@@ -39,6 +41,7 @@
 
 import qualified Data.ConfigManager.Reader as R
 import Data.ConfigManager.Types
+import Data.ConfigManager.Instances ()
 
 -- | Load a 'Config' from a given 'FilePath'.
 
@@ -47,13 +50,13 @@
 
 -- | Lookup for the value associated to a name.
 
-lookup :: Read a => Name -> Config -> Either Text a
+lookup :: Configured a => Name -> Config -> Either Text a
 lookup name config =
   case M.lookup name (hashMap config) of
     Nothing ->
       Left . T.concat $ ["Value not found for Key ", name]
     Just value ->
-      case readMaybe . T.unpack $ value of
+      case convert value of
         Nothing -> Left . T.concat $ ["Reading error for key ", name]
         Just result -> Right result
 
@@ -80,8 +83,11 @@
 -- > a_double = 4.0
 -- > thatIsABoolean = True
 -- > a_double = 5.0
+-- > diffTime = 1 day
+-- > otherDiffTime = 3 hours
 --
--- If two or more bindings have the same name, only the last one is kept.
+-- * If two or more bindings have the same name, only the last one is kept.
+-- * Accepted duration values are seconds, minutes, hours, days and weeks.
 
 -- $import
 --
@@ -96,3 +102,35 @@
 --
 -- > # Comment
 -- > x = 8 # Another comment
+
+-- $example
+--
+-- From application.conf:
+--
+-- > port = 3000
+-- > mailFrom = "no-reply@mail.com"
+-- > currency = "$"
+-- > expiration = 30 minutes
+--
+-- Read the configuration:
+--
+-- > import qualified Data.ConfigManager as Conf
+-- > import Data.Time.Clock (DiffTime)
+-- >
+-- > data Conf = Conf
+-- >   { port :: Int
+-- >   , mailFrom :: String
+-- >   , currency :: String
+-- >   , expiration :: DiffTime
+-- >   } deriving (Read, Eq, Show)
+-- >
+-- > getConfig :: IO (Either Text Conf)
+-- > getConfig =
+-- >   (flip fmap) (Conf.readConfig "application.conf") (\configOrError -> do
+-- >     conf <- configOrError
+-- >     Conf <$>
+-- >       Conf.lookup "port" conf <*>
+-- >       Conf.lookup "mailFrom" conf <*>
+-- >       Conf.lookup "currency" conf <*>
+-- >       Conf.lookup "expiration" conf
+-- >   )
diff --git a/Data/ConfigManager/Instances.hs b/Data/ConfigManager/Instances.hs
new file mode 100644
--- /dev/null
+++ b/Data/ConfigManager/Instances.hs
@@ -0,0 +1,24 @@
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE IncoherentInstances #-}
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Data.ConfigManager.Instances
+  () where
+
+import qualified Data.Text as T
+import Data.Time.Clock (DiffTime, NominalDiffTime)
+
+import Text.Read (readMaybe)
+
+import Data.ConfigManager.Types.Internal
+import Data.ConfigManager.Parser.Duration (parseDuration)
+
+instance Configured DiffTime where
+  convert value = parseDuration value
+
+instance Configured NominalDiffTime where
+  convert value = realToFrac <$> parseDuration value
+
+instance Read a => Configured a where
+  convert = readMaybe . T.unpack
diff --git a/Data/ConfigManager/Parser/Duration.hs b/Data/ConfigManager/Parser/Duration.hs
new file mode 100644
--- /dev/null
+++ b/Data/ConfigManager/Parser/Duration.hs
@@ -0,0 +1,36 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Data.ConfigManager.Parser.Duration
+  ( parseDuration
+  ) where
+
+import Control.Applicative ((<|>))
+
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.Time.Clock (DiffTime)
+import qualified Data.Time.Clock as Time
+
+import Text.Read (readMaybe)
+
+parseDuration :: Text -> Maybe DiffTime
+parseDuration input =
+  case T.splitOn " " input of
+    [count, unit] -> do
+      n <- readMaybe . T.unpack $ count
+      let matchDuration singularUnit pluralUnit seconds =
+            if ((n == 0 || n == 1) && unit == singularUnit) || (n > 1 && unit == pluralUnit)
+              then Just . Time.secondsToDiffTime $ n * seconds
+              else Nothing
+      (matchDuration "second" "seconds" second)
+        <|> (matchDuration "minute" "minutes" minute)
+        <|> (matchDuration "hour" "hours" hour)
+        <|> (matchDuration "day" "days" day)
+        <|> (matchDuration "week" "weeks" week)
+    _ -> Nothing
+  where
+    second = 1
+    minute = 60 * second
+    hour = 60 * minute
+    day = 24 * hour
+    week = 7 * day
diff --git a/Data/ConfigManager/Reader.hs b/Data/ConfigManager/Reader.hs
--- a/Data/ConfigManager/Reader.hs
+++ b/Data/ConfigManager/Reader.hs
@@ -43,8 +43,8 @@
     Binding name value ->
       return . Right . Config $ M.insert name value (hashMap config)
     Import requirement path -> do
-      eitherConfig <- readConfig requirement (fileDir </> path)
-      case eitherConfig of
+      configOrError <- readConfig requirement (fileDir </> path)
+      case configOrError of
         Left errorMessage ->
           return . Left $ errorMessage
         Right importedConfig ->
diff --git a/Data/ConfigManager/Types.hs b/Data/ConfigManager/Types.hs
--- a/Data/ConfigManager/Types.hs
+++ b/Data/ConfigManager/Types.hs
@@ -12,6 +12,8 @@
   , Name
   , Value
   , Requirement(..)
+  , Configured
+  , convert
   ) where
 
 import Data.ConfigManager.Types.Internal
diff --git a/Data/ConfigManager/Types/Internal.hs b/Data/ConfigManager/Types/Internal.hs
--- a/Data/ConfigManager/Types/Internal.hs
+++ b/Data/ConfigManager/Types/Internal.hs
@@ -4,10 +4,11 @@
   , Name
   , Value
   , Requirement(..)
+  , Configured
+  , convert
   ) where
 
 import Data.Text (Text)
-
 import Data.HashMap.Strict
 
 -- | Configuration data.
@@ -37,3 +38,9 @@
   Required
   | Optional
   deriving (Eq, Read, Show)
+
+-- | This class represents types that can be converted /from/ a value /to/ a
+-- destination type
+
+class Configured a where
+  convert :: Value -> Maybe a
diff --git a/config-manager.cabal b/config-manager.cabal
--- a/config-manager.cabal
+++ b/config-manager.cabal
@@ -1,5 +1,5 @@
 name:                  config-manager
-version:               0.1.0.0
+version:               0.2.0.0
 synopsis:              Configuration management
 description:
   A configuration management library which supports:
@@ -9,6 +9,9 @@
   * required or optional imports,
   .
   * comments.
+  .
+  For details of the configuration file format, see
+  <http://hackage.haskell.org/packages/archive/config-manager/latest/doc/html/Data-ConfigManager.html>.
 homepage:              https://gitlab.com/guyonvarch/config-manager
 bug-reports:           https://gitlab.com/guyonvarch/config-manager/issues
 license:               GPL-3
@@ -26,13 +29,16 @@
                        Data.ConfigManager.Types
   other-modules:       Data.ConfigManager.Reader
                        Data.ConfigManager.Parser
+                       Data.ConfigManager.Instances
                        Data.ConfigManager.Types.Internal
+                       Data.ConfigManager.Parser.Duration
   ghc-options:         -Wall
   build-depends:       base < 5,
                        text,
                        unordered-containers,
                        parsec,
-                       filepath
+                       filepath,
+                       time
   default-language:    Haskell2010
 
 source-repository      head
@@ -52,5 +58,6 @@
                        test-framework-hunit,
                        temporary,
                        directory,
-                       unordered-containers
+                       unordered-containers,
+                       time
   default-language:    Haskell2010
diff --git a/tests/Test.hs b/tests/Test.hs
--- a/tests/Test.hs
+++ b/tests/Test.hs
@@ -18,6 +18,8 @@
 import Data.ConfigManager
 import Data.ConfigManager.Types (Config(..))
 import qualified Data.Text as T
+import Data.Time.Clock (DiffTime)
+import qualified Data.Time.Clock as Time
 
 import Helper (forceGetConfig, getConfig, eitherToMaybe)
 
@@ -32,6 +34,7 @@
   , testCase "value" valueAssertion
   , testCase "skip" skipAssertion
   , testCase "import" importAssertion
+  , testCase "duration" durationAssertion
   ]
 
 bindingAssertion :: Assertion
@@ -41,7 +44,7 @@
 
   oneBinding <- forceGetConfig "x = \"foo\""
   assertEqual "one binding present" (Right "foo") (lookup "x" oneBinding)
-  assertBool "one binding missing" (isLeft $ (lookup "y" oneBinding :: Either Text Int))
+  assertBool "one binding missing" (isLeft (lookup "y" oneBinding :: Either Text Int))
   assertEqual "one binding count" 1 (M.size . hashMap $ oneBinding)
 
   multipleBindings <- forceGetConfig $ T.unlines
@@ -133,3 +136,40 @@
     , "x = 4"
     ]
   assertEqual "missing optional config" (Right 4) (lookup "x" missingOptionalConfig)
+
+durationAssertion :: Assertion
+durationAssertion = do
+  config <- forceGetConfig $ T.unlines
+    [ "a = 1 second"
+    , "b = 5 seconds"
+    , "c = 1 minute"
+    , "d = 10 minutes"
+    , "e = 1 hour"
+    , "f = 7 hours"
+    , "g = 1 day"
+    , "h = 2 days"
+    , "i = 1 week"
+    , "j = 9 weeks"
+    , ""
+    , "k = 1 minutes"
+    , "l = 20  weeks"
+    ]
+
+  let second = 1
+  let minute = 60 * second
+  let hour = 60 * minute
+  let day = 24 * hour
+  let week = 7 * day
+
+  assertEqual "a" (Right (Time.secondsToDiffTime $ 1 * second)) (lookup "a" config)
+  assertEqual "b" (Right (Time.secondsToDiffTime $ 5 * second)) (lookup "b" config)
+  assertEqual "c" (Right (Time.secondsToDiffTime $ 1 * minute)) (lookup "c" config)
+  assertEqual "d" (Right (Time.secondsToDiffTime $ 10 * minute)) (lookup "d" config)
+  assertEqual "e" (Right (Time.secondsToDiffTime $ 1 * hour)) (lookup "e" config)
+  assertEqual "f" (Right (Time.secondsToDiffTime $ 7 * hour)) (lookup "f" config)
+  assertEqual "g" (Right (Time.secondsToDiffTime $ 1 * day)) (lookup "g" config)
+  assertEqual "h" (Right (Time.secondsToDiffTime $ 2 * day)) (lookup "h" config)
+  assertEqual "i" (Right (Time.secondsToDiffTime $ 1 * week)) (lookup "i" config)
+  assertEqual "j" (Right (Time.secondsToDiffTime $ 9 * week)) (lookup "j" config)
+  assertBool "k" (isLeft (lookup "k" config :: Either Text DiffTime))
+  assertBool "l" (isLeft (lookup "l" config :: Either Text DiffTime))