How is it determined what key playing or singing in by looking at the music?

Answer 1

Look at the key signature.

Look at where the end of the song resolves.

Answer 2

Using sheet music, you will look at the key signature next to the time signature at the beginning of the music to determine the key. When in doubt, use the circle of fifths to help you out. Accidentals and cadences often give us the information needed to determine major/minor when necessary.

Answer 3

-If a piece of music is in only one key, it will use notes from one scale. For example, a piece in the key of G major uses G-A-B-C-D-E and F#.

Look at the key signature. Does it have only one sharp?

Next, look at the last measure. Does the piece end on G, or a G chord (G-B-D)? If the answer to these questions is yes, the piece is likely in the key of G.

If you're not sure which sharps and flats are in each key signature, look up a chart called the Circle of Fifths. It is a useful tool for determining key signatures.

Hope this helps!

Answer 4

Some pieces of music change keys, or move from one key to another in a different section. Even when that isn't the case, it isn't always clear. Here are some ways to guess:

1. Look at the key signature
2. Look at the first chord
3. Look at the last chord
4. Look at the final cadence, is there a definitive V - I motion at some point, or multiple points?
5. What is the most often used chord or cadence in the piece?

Once you've done all that, you can play through the song and use your sense to determine where the stable or arrival point is, the point that feels like "home."

Some songs use what's called a "shuttle progression." It may be two related chords in one key, and two related chords in another key, and they're each of equal length.

Not all pieces of music are in one key, nor do they need to be. Some music has no clear key at all.

The short answer is, it's complicated, and it depends on a lot of things. But being aware of that is the key (pun intended) to understanding how key centers work, and to avoid getting stuck when trying to determine what the key is. The truth is there may not be just one key, and another truth is that what the key is doesn't matter at all sometimes.