Part of our section on Musical Notation where we look at the elements of a music score.
This page follows on from our page on key signatures.
The time signature follows the clef sign and the key signature.
The time signature consists of 2 numbers. In the example below both numbers are 4, one above the other, “4 over 4”, or “4 / 4”, or just “four four”.
The top number tells us how many beats are in each bar, so there are 4 beats to a bar.
The bottom number tells us what each beat consists of, in this case crotchets which are also known as “quarter notes”, hence “over 4”.
Unlike the key signature, the time signature is not usually repeated at the start of each line.
A new time signature will only be written if and when it changes.
Note that the time signature only tells us about the bar length and rhythm of a passage of music. It does not tell us the speed of the music i.e. how much time does each beat last for, or how many beats per minute (bpm). For this you need to see our page on Tempo.
Here are some other examples of time signatures:
3 / 4 time is 3 beats to a bar where each beat is a crotchet (quarter note).
2 / 4 time is 2 beats to a bar where each beat is a crotchet (quarter note).
2 / 2 time is 2 beats to a bar where each beat is a minim (half note).
3 / 8 time is 3 beats to a bar where each beat is a quaver (eighth note).
You may also come across these time signatures:
Common time is the same as 4 4 i.e. 4 crotchet beats in a bar
Cut common time is the same as 2 2 i.e. 2 minim beats in a bar
The above are all examples of “simple time”.
Here are some examples of time signatures known as “compound time”:
In compound time the top number is always a multiple of 3 such as 6, 9 or 12, and the notes are grouped 3 to a beat.
6 / 8 time is 2 beats to a bar where each beat consists of 3 quavers (eighth notes).
9 / 8 time is 3 beats to a bar where each beat consists of 3 quavers (eighth notes).
6 / 4 time is 2 beats to a bar where each beat consists of 3 crotchets (quarter notes).
But note that the time signature 6 / 4 could also be used to indicate 6 beats to a bar where each beat is a crotchet (quarter note). The context should make it clear.
A good example of the difference between simple and compound time is in the song America from the musical West Side Story:
The tune uses alternate bars of 6 / 8 (compound time) and 3 / 4 (simple time) in a very interesting way as you can hear. Each bar is the same length, since 6 quavers take the same time as 3 crotchets, but has a very different rhythm. The 6 / 8 bars have 2 beats as “Da-da-da Da-da-da” while the 3 / 4 bars have 3 beats as “Da Da Da”.
Treat yourself to the 2021 cast singing America:
Find out more about time signatures on simple wikipedia
Continue to explore musical notation on our page about note values
Return to Musical Notation