diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+0.4.2
+-----
+* Added `clamp`
+
 0.4
 ---
 * Distributive Interval
diff --git a/intervals.cabal b/intervals.cabal
--- a/intervals.cabal
+++ b/intervals.cabal
@@ -1,5 +1,5 @@
 name:              intervals
-version:           0.4.1
+version:           0.4.2
 synopsis:          Interval Arithmetic
 description:
   A 'Numeric.Interval.Interval' is a closed, convex set of floating point values.
diff --git a/src/Numeric/Interval.hs b/src/Numeric/Interval.hs
--- a/src/Numeric/Interval.hs
+++ b/src/Numeric/Interval.hs
@@ -40,6 +40,7 @@
   , isSubsetOf
   , certainly, (<!), (<=!), (==!), (>=!), (>!)
   , possibly, (<?), (<=?), (==?), (>=?), (>?)
+  , clamp
   , idouble
   , ifloat
   ) where
@@ -720,6 +721,12 @@
         eq = cmp EQ EQ
         gt = cmp GT EQ
 {-# INLINE possibly #-}
+
+-- | The nearest value to that supplied which is contained in the interval.
+clamp :: Ord a => Interval a -> a -> a
+clamp (I a b) x | x < a     = a
+                | x > b     = b
+                | otherwise = x
 
 -- | id function. Useful for type specification
 --