As easily as a thermometer tells you the temperature, KeyOmeter automatically determines and displays the musical key. KeyOmeter operates in the "circle of fifths" -- a visual representation of the 12 tonal centers or keys of the Western chromatic scale. The outer circle displays the twelve major keys, the inner circle shows their relative minors. Most music is not in a single key but modulates from one key to another. KeyOmeter follows and displays changes in key over time in live music.

What’s New

Version 2.1

Audiobus 3 compatible.

Ratings and Reviews

4.0 out of 5
1 Rating

1 Rating

Filter_Emphasis ,

Yes it does work

This app is a surprise. A few of us have been experimenting with this app using our own recorded compositions, or playing on a piano and also using songs from the radio. The app is often exactly correct. The app requires a bit of musical knowledge to interpret what it is telling you. We are very happy with this app and use it often.

I would appreciate the developer saying a few words about the new audiobus support. I currently do not own the audiobus app and as it costs $10 would like to know exactly what the benefit of this new feature would be to me. I use AUM which is similar to Audiobus, does this mean I can take advantage of the new feature without buying Audiobus?

The very short update detail by the developer leaves many questions!

Ksdwws ,


This app does not work! Don't waste your money!!!

bobtheowl2 ,


Worked in brief validation test. Very helpful to be able to quickly determine how to play along with. Would be nice to see notes detected real time too but looks like he has another app that does that too.


Mark Carlotto
6 MB

Requires iOS 10.3 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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