What's New

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

Updated for newer devices.

App Description

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.

iPhone Screenshots

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What Key screenshot 1 What Key screenshot 2 What Key screenshot 3

iPad Screenshots

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What Key screenshot 4 What Key screenshot 5 What Key screenshot 6

App Changes

  • March 28, 2012 New version 2.2
  • July 13, 2012 New version 3.0
  • September 04, 2012 New version 3.1
  • October 05, 2012 New version 3.2
  • February 04, 2013 New version 3.3
  • February 13, 2013 New version 3.4
  • July 12, 2013 Price increase: $1.99 -> $2.99
  • September 29, 2013 New version 3.5
  • March 12, 2015 Price decrease: $2.99 -> $1.99
  • July 29, 2015 New version 3.5.1
  • June 15, 2019 New version 3.6