diff --git a/AUTHORS.md b/AUTHORS.md
index 63bd4ad..56c7518 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -1,3 +1,4 @@
 ## AUTHORS
+- [Dominik Honnef](https://github.com/dominikh) dominik@honnef.co
 - [Dong-hee Na](https://github.com/corona10/) donghee.na92@gmail.com
 - [Gustavo Brunoro](https://github.com/brunoro/) git@hitnail.net
diff --git a/hashcompute_test.go b/hashcompute_test.go
index 5502098..47e6c71 100644
--- a/hashcompute_test.go
+++ b/hashcompute_test.go
@@ -97,3 +97,21 @@ func TestHashCompute(t *testing.T) {
 		}
 	}
 }
+
+func BenchmarkDistanceIdentical(b *testing.B) {
+	h1 := &ImageHash{hash: 0xe48ae53c05e502f7}
+	h2 := &ImageHash{hash: 0xe48ae53c05e502f7}
+
+	for i := 0; i < b.N; i++ {
+		h1.Distance(h2)
+	}
+}
+
+func BenchmarkDistanceDifferent(b *testing.B) {
+	h1 := &ImageHash{hash: 0xe48ae53c05e502f7}
+	h2 := &ImageHash{hash: 0x678be53815e510f7} // 8 bits flipped
+
+	for i := 0; i < b.N; i++ {
+		h1.Distance(h2)
+	}
+}
diff --git a/imagehash.go b/imagehash.go
index 785a34b..da0af93 100644
--- a/imagehash.go
+++ b/imagehash.go
@@ -42,17 +42,11 @@ func (h *ImageHash) Distance(other *ImageHash) (int, error) {
 		return -1, errors.New("Image hashes's kind should be identical")
 	}
 
-	diff := 0
 	lhash := h.GetHash()
 	rhash := other.GetHash()
 
 	hamming := lhash ^ rhash
-	for hamming != 0 {
-		diff += int(hamming & 1)
-		hamming >>= 1
-	}
-
-	return diff, nil
+	return popcnt(hamming), nil
 }
 
 // GetHash method returns a 64bits hash value.
diff --git a/imagehash18.go b/imagehash18.go
new file mode 100644
index 0000000..e8d3fd6
--- /dev/null
+++ b/imagehash18.go
@@ -0,0 +1,13 @@
+// +build !go1.9
+
+package goimagehash
+
+func popcnt(x uint64) int {
+	diff := 0
+	for x != 0 {
+		diff += int(x & 1)
+		x >>= 1
+	}
+
+	return diff
+}
diff --git a/imagehash19.go b/imagehash19.go
new file mode 100644
index 0000000..c1d47be
--- /dev/null
+++ b/imagehash19.go
@@ -0,0 +1,9 @@
+// +build go1.9
+
+package goimagehash
+
+import (
+	"math/bits"
+)
+
+func popcnt(x uint64) int { return bits.OnesCount64(x) }