# What Key

> Real-time musical key detection app supporting multiple scales. (iPhone/iPad app by Mark Carlotto.)

- Source: https://appshunter.io/ios/app/what-key/id302005959 (this page in markdown: same URL + `.md`)
- Developer: [Mark Carlotto](https://appshunter.io/developer/293347135)
- Category: Music, Education
- Price: $1.99
- Rating: 1.80/5 from 5 App Store ratings · 17 written reviews indexed
- Age rating: 4+
- Requires: iOS 8.2 · 4 MB
- Languages: English
- Released: 2009-01-15
- Data updated: 2026-06-10
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/what-key/id302005959/reviews.md

## What is What Key?

What Key is a key detection app that determines the musical key of a song in real time. Using the pitch detection algorithm from Pitch to Note, What Key matches the notes being played to major, minor, blues, bebop (jazz) and other scales in all keys, picking the scale and key with the best match. 

What Key is a universal app that runs on iPod Touch, iPhone, and iPad.

What Key works best on music with minimal percussion tuned to A4=440 Hz.

## Key features

- Real-time key detection
- Supports major, minor, blues, bebop scales
- Pitch detection algorithm
- Universal app compatibility
- Optimized for music with minimal percussion

## Recent user reviews (10 of 17)

All indexed reviews: https://appshunter.io/ios/app/what-key/id302005959/reviews.md

### 1/5 — Piece of crap

*2018-11-25, version 3.6*

Doesn’t work. And if there’s something I’m doing wrong there’s nothing to help me. Do not waste your money like I did.

### 5/5 — Great App after I learned how to configure

*2017-02-27, version 3.6*

I have owned this for a long time, and rely on it to find keys to songs I want to learn to play.  
The best way to get highly precise readings on this app is to be sure your settings are configured correctly.  I recommend going the settings tab and turning off all scales except "major".  If you do this, most songs will pop up correctly and stay the same during the entire song. 

HOWEVER, if you have an ability to hear and recognize minor keys, and you are testing a song that you suspect may be in a minor key - turn off the "major" scale and turn on the "melodic minor" scale and give it a try.  Also if you know how to recognize a blues tune, you may get good results from setting the scales to "major and minor pentatonic."  
If you just turn on all scales, the display is going to show multiple options at any given point during a song.  It may also be worth noting that some scales are essentially the same but with a different starting place (ie G major Em) so if you have a bit of music theory to help you you will enjoy the app more.

### 1/5 — Don't work

*2017-02-07, version 3.6*

I tried using it with my iTunes it just shuts it off waste of money!

### 1/5 — The app didn't make a sound

*2016-02-24, version 3.5.1*

Not a goddam sound

### 1/5 — Word to the wise don't buy this app!

*2015-02-11, version 3.5*

Complete was of time! If you value your don't move on to another solution this app doesn't work!

### 1/5 — No good

*2014-11-01, version 3.5*

Does not work at all it's totally useless!!!!!!

### 2/5 — Good idea

*2014-09-21, version 3.5*

App does not work! Tried to use it while playing the piano and it couldn't even find the piano note. Hopefully there is a return policy on the App Store!

### 1/5 — Worthless

*2014-04-14, version 3.5*

This app is a total fail. It never works - not ever.

### 1/5 — What a great idea

*2013-10-30, version 3.5*

What a disappointment!  Hopefully in a near update this will be fixed to where it actually does what it says it does!

### 1/5 — Good idea, but...

*2013-09-24, version 3.4*

This app is really great in theory and I was super excited to use it, but it won't open. The app crashes before it even gets to a home screen. $3.00 down the drain :/

## Frequently asked questions about What Key

### What is the price of What Key?

What Key is a paid application, priced at $1.99. This one-time purchase grants you access to all its features.

### What devices does What Key support?

What Key is a universal app and runs on iPhone, iPad, and iPod Touch devices. It is designed to function across Apple's mobile ecosystem.

### How accurate is What Key's key detection?

What Key uses a pitch detection algorithm to match notes to scales and keys. It works best on music with minimal percussion and tuned to A4=440 Hz for optimal results.

### What musical scales can What Key detect?

What Key can detect major, minor, blues, and bebop (jazz) scales, among others. It identifies the scale and key with the best match to the music being played.

### When was What Key last updated?

The latest version of What Key was released on January 7, 2017. The app has been available since its initial release on January 15, 2009.

### What is the age rating for What Key?

What Key has an age rating of 4+. This indicates it is suitable for users of all ages, with no mature content.

### What do users think of What Key?

User feedback for What Key is mixed, with an average rating of 1.8 stars from 5 ratings. This suggests potential areas for improvement in user experience or functionality.

## Version history (last 1 release)

### 3.6 — 2017-01-07

This app has been updated by Apple to display the Apple Watch app icon.

Updated for newer devices.

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## More apps by Mark Carlotto

- [Pitch To Note](https://appshunter.io/ios/app/pitch-to-note/id293347132)
- [Audio to MIDI](https://appshunter.io/ios/app/audio-to-midi/id320560554)
- [KML Map](https://appshunter.io/ios/app/kml-map/id347857461)
- [EZ 3-D Photo](https://appshunter.io/ios/app/ez-3-d-photo/id401437046)
- [3-D Movie Camera](https://appshunter.io/ios/app/3-d-movie-camera/id410331993)

All apps by Mark Carlotto: https://appshunter.io/developer/293347135

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*