diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Changelog for interval-algebra
 
+## 0.10.2
+
+* Adds the `momentize` function for changing the duration of some interval value to a moment.
+
 ## 0.10.1
 
 * Replaces unnecessary `IntervalCombinable i0 a` constraint in `gapsWithin` with `Intervallic i0 a`.
diff --git a/interval-algebra.cabal b/interval-algebra.cabal
--- a/interval-algebra.cabal
+++ b/interval-algebra.cabal
@@ -1,6 +1,6 @@
 cabal-version:  2.2
 name:           interval-algebra
-version:        0.10.1
+version:        0.10.2
 synopsis:       An implementation of Allen's interval algebra for temporal logic
 description:    Please see the README on GitHub at <https://github.com/novisci/interval-algebra>
 category:       Algebra,Time
diff --git a/src/IntervalAlgebra.hs b/src/IntervalAlgebra.hs
--- a/src/IntervalAlgebra.hs
+++ b/src/IntervalAlgebra.hs
@@ -159,6 +159,7 @@
     , endervalFromBegin
     , diffFromBegin
     , diffFromEnd
+    , momentize
 
     -- ** Algebraic operations
     , intervalRelations
@@ -673,6 +674,16 @@
                , Intervallic i0 a ) => 
     i0 a -> i1 a -> i1 b
 diffFromEnd i = fmap (`diff` end i)
+
+-- | Changes the duration of an 'Intervallic' value to a moment starting at the 
+--   'begin' of the interval.
+-- 
+-- >>> momentize (Interval (6, 10))
+-- (6, 7)
+--
+momentize :: ( IntervalSizeable a b, Intervallic i a ) =>
+    i a -> i a
+momentize i = setInterval i (beginerval (moment' i) (begin i))
 
 {- |
 The @'IntervalCombinable'@ typeclass provides methods for (possibly) combining
diff --git a/src/IntervalAlgebra/Arbitrary.hs b/src/IntervalAlgebra/Arbitrary.hs
--- a/src/IntervalAlgebra/Arbitrary.hs
+++ b/src/IntervalAlgebra/Arbitrary.hs
@@ -9,6 +9,7 @@
 {-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE Safe #-}
+{-# LANGUAGE TypeApplications #-}
 
 module IntervalAlgebra.Arbitrary() where
 
diff --git a/test/IntervalAlgebraSpec.hs b/test/IntervalAlgebraSpec.hs
--- a/test/IntervalAlgebraSpec.hs
+++ b/test/IntervalAlgebraSpec.hs
@@ -68,7 +68,8 @@
                                   , Interval
                                   , IntervalRelation (..)
                                   , intervalRelations
-                                  , notDisjoint )
+                                  , notDisjoint
+                                  , momentize )
 
 mkIntrvl :: Int -> Int -> Interval Int
 mkIntrvl = beginerval
@@ -656,6 +657,13 @@
             (beginerval 2 (fromGregorian 2001 1 1))
             (beginerval 2 (fromGregorian 2001 1 10)) `shouldBe`
             beginerval 2 7 -- (7, 9)
+
+      it "momentize works" $
+         momentize
+            (beginerval 2 (fromGregorian 2001 1 1))
+            `shouldBe`
+            beginerval 1 (fromGregorian 2001 1 1)
+
 
   describe "Intervallic tests" $
      modifyMaxSuccess (*10000) $