diff --git a/package.json b/package.json
index 03881da..a174aa4 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "1.0.3",
+  "version": "1.0.4",
   "license": "MIT",
   "main": "dist/index.js",
   "typings": "dist/index.d.ts",
diff --git a/src/services/caches.ts b/src/services/caches.ts
new file mode 100644
index 0000000..d10a60c
--- /dev/null
+++ b/src/services/caches.ts
@@ -0,0 +1,7 @@
+export const getKeyOctave = new Map()
+
+export const getOctaveCompleteness = new Map()
+
+export const getKeyXOffset = new Map()
+
+export const isNaturalKey = new Map()
diff --git a/src/services/getFractionalOctaveCount.ts b/src/services/getFractionalOctaveCount.ts
index 849872e..787d0fb 100644
--- a/src/services/getFractionalOctaveCount.ts
+++ b/src/services/getFractionalOctaveCount.ts
@@ -2,8 +2,9 @@ import mem from 'mem'
 import generateKeys from './generateKeys'
 import groupKeysIntoOctaves from './groupKeysIntoOctaves'
 import getOctaveCompletenessUnmemoized from './getOctaveCompleteness'
+import * as caches from './caches'
 
-const getOctaveCompleteness = mem(getOctaveCompletenessUnmemoized)
+const getOctaveCompleteness = mem(getOctaveCompletenessUnmemoized, { cache: caches.getOctaveCompleteness })
 
 interface GetFractionalOctaveCount {
   (startKey: number, endKey: number): number
diff --git a/src/services/getKeyLeft.ts b/src/services/getKeyLeft.ts
index 4a7f0ea..e3025ae 100644
--- a/src/services/getKeyLeft.ts
+++ b/src/services/getKeyLeft.ts
@@ -3,11 +3,12 @@ import getKeyXOffsetUnmemoized from './getKeyXOffset'
 import getOctaveCountUnmemoized from './getOctaveCount'
 import getFractionalOctaveCountUnmemoized from './getFractionalOctaveCount'
 import getKeyOctaveUnmemoized from './getKeyOctave'
+import * as caches from './caches'
 
-const getKeyXOffset = mem(getKeyXOffsetUnmemoized)
+const getKeyXOffset = mem(getKeyXOffsetUnmemoized, { cache: caches.getKeyXOffset })
 const getOctaveCount = mem(getOctaveCountUnmemoized, { cacheKey: (args) => args.join(':') })
 const getFractionalOctaveCount = mem(getFractionalOctaveCountUnmemoized, { cacheKey: (args) => args.join(':') })
-const getKeyOctave = mem(getKeyOctaveUnmemoized)
+const getKeyOctave = mem(getKeyOctaveUnmemoized, { cache: caches.getKeyOctave })
 
 export interface GetKeyLeft {
   (k: number): number
diff --git a/src/services/getKeyWidth.ts b/src/services/getKeyWidth.ts
index a4b650a..2d71b71 100644
--- a/src/services/getKeyWidth.ts
+++ b/src/services/getKeyWidth.ts
@@ -3,6 +3,7 @@ import isNaturalKeyUnmemoized from './isNaturalKey'
 import getOctaveCountUnmemoized from './getOctaveCount'
 import getFractionalOctaveCountUnmemoized from './getFractionalOctaveCount'
 import { ACCIDENTAL_KEY_TO_NATURAL_KEY_WIDTH_RATIO } from './constants'
+import * as caches from './caches'
 
 export interface GetKeyWidth {
   (k: number): number
@@ -12,19 +13,17 @@ interface GetKeyWidthDecorator {
   (startKey: number, endKey: number): GetKeyWidth
 }
 
-const isNaturalKey = mem(isNaturalKeyUnmemoized)
-const getFractionalOctaveCount = mem(getFractionalOctaveCountUnmemoized, { cacheKey: (args) => args.join(':') })
+const isNaturalKey = mem(isNaturalKeyUnmemoized, { cache: caches.isNaturalKey })
+const getFractionalOctaveCount = mem(getFractionalOctaveCountUnmemoized, {
+  cacheKey: (args) => args.join(':'),
+})
 const getOctaveCount = mem(getOctaveCountUnmemoized, { cacheKey: (args) => args.join(':') })
 
-const getKeyWidthDecorator: GetKeyWidthDecorator = (startKey, endKey) => {
-  const getKeyWidth: GetKeyWidth = (k) => {
-    const fractionalOctaveCount = getFractionalOctaveCount(startKey, endKey)
-    const octaveCount = getOctaveCount(startKey, endKey)
-    const naturalKeyWidth = (100 * (octaveCount / fractionalOctaveCount)) / (octaveCount * 7)
-    return isNaturalKey(k) ? naturalKeyWidth : naturalKeyWidth * ACCIDENTAL_KEY_TO_NATURAL_KEY_WIDTH_RATIO
-  }
-
-  return mem(getKeyWidth)
+const getKeyWidthDecorator: GetKeyWidthDecorator = (startKey, endKey) => (k) => {
+  const fractionalOctaveCount = getFractionalOctaveCount(startKey, endKey)
+  const octaveCount = getOctaveCount(startKey, endKey)
+  const naturalKeyWidth = (100 * (octaveCount / fractionalOctaveCount)) / (octaveCount * 7)
+  return isNaturalKey(k) ? naturalKeyWidth : naturalKeyWidth * ACCIDENTAL_KEY_TO_NATURAL_KEY_WIDTH_RATIO
 }
 
 export default getKeyWidthDecorator
diff --git a/src/services/getOctaveCompleteness.ts b/src/services/getOctaveCompleteness.ts
index af1b393..f25e5c9 100644
--- a/src/services/getOctaveCompleteness.ts
+++ b/src/services/getOctaveCompleteness.ts
@@ -1,9 +1,10 @@
 import mem from 'mem'
+import * as caches from './caches'
 import getKeyXOffsetUnmemoized from './getKeyXOffset'
 import isNaturalKeyUnmemoized from './isNaturalKey'
 
-const getKeyXOffset = mem(getKeyXOffsetUnmemoized)
-const isNaturalKey = mem(isNaturalKeyUnmemoized)
+const getKeyXOffset = mem(getKeyXOffsetUnmemoized, { cache: caches.getKeyXOffset })
+const isNaturalKey = mem(isNaturalKeyUnmemoized, { cache: caches.isNaturalKey })
 
 interface GetOctaveCompleteness {
   (firstKey: number, lastKey: number): number
diff --git a/src/services/getOctaveCount.ts b/src/services/getOctaveCount.ts
index a743d6f..6902786 100644
--- a/src/services/getOctaveCount.ts
+++ b/src/services/getOctaveCount.ts
@@ -1,7 +1,8 @@
 import mem from 'mem'
 import getKeyOctaveUnmemoized from './getKeyOctave'
+import * as caches from './caches'
 
-const getKeyOctave = mem(getKeyOctaveUnmemoized)
+const getKeyOctave = mem(getKeyOctaveUnmemoized, { cache: caches.getKeyOctave })
 
 interface GetOctaveCount {
   (startKey: number, endKey: number): number