diff --git a/src/Data.Range.purs b/src/Data.Range.purs
index a726f3c..3c02f65 100644
--- a/src/Data.Range.purs
+++ b/src/Data.Range.purs
@@ -15,6 +15,10 @@ data Bound a
   = BoundIncluding a
   | BoundExcluding a
 
+instance Functor Bound where
+  map f (BoundIncluding a) = BoundIncluding $ f a
+  map f (BoundExcluding a) = BoundExcluding $ f a
+
 derive instance Generic (Bound a) _
 derive instance Ord a => Ord (Bound a)
 derive instance Eq a => Eq (Bound a)
@@ -44,6 +48,11 @@ derive instance Eq a => Eq (Range a)
 instance Show a => Show (Range a) where
   show = genericShow
 
+instance Functor Range where
+  map f (RangeAbove b) = RangeAbove $ map f b
+  map f (RangeBelow b) = RangeBelow $ map f b
+  map f (RangeBetween a b) = RangeBetween (map f a) (map f b)
+
 instance Semigroup (Range a) where
   append (RangeAbove a) (RangeBelow b) = RangeBetween a b
   append (RangeBelow a) (RangeAbove b) = RangeBetween a b