This site aims to help users like you determine what key a piece of music is in. Understanding key signitures is mostly straightforward, but there is a little bit of nuance involved.
The first thing to look at is if the key signiture uses flats (♭) or sharps (#).
If your key signiture has flats, refer to list below. If it has sharps, scroll down a bit to find that list. If your key signiture has no sharps or flats, the key is either C Major or A Minor. I will explain the difference and how to tell in the next section.
- 1 Flat: F Major or D Minor
- 2 Flats: B♭ Major or G Minor
- 3 Flats: E♭ Major or C Minor
- 4 Flats: A♭ Major or F Minor
- 5 Flats: D♭ Major or B♭ Minor
- 6 Flats: G♭ Major or E♭ Minor
- 7 Flats: C♭ Major or A♭ Minor
If your key signiture has sharps, refer to this list.
- 1 Sharp: G Major or E Minor
- 2 Sharps: D Major or B Minor
- 3 Sharps: A Major or F# Minor
- 4 Sharps: E Major or C# Minor
- 5 Sharps: B Major or G# Minor
- 6 Sharps: F# Major or D# Minor
- 7 Sharps: C# Major or B# Minor
After you have determined the two possible keys, there is a bit of nuance that goes into figuring out which one it is. Musical context is the way one would normally determine the key, but if you have little understanding of music theory, the easiest way to tell is to listen to a bit of the piece and see if it sounds happy or sad.