A time signature is an indicator of the rhythmic parameters of a piece of music. It consists of two numbers (one stacked on top of the other). Each number tells us something about the way the rhythms of the piece should be read and counted. The top number tells us how many beats are contained in each measure of the piece. The bottom number tells us which note receives the value of one beat in this piece of music.

Time signatures are located in the beginning of a piece of music. The first symbol to the very left of the musical staff is the clef. This tells us which five lines are represented by the staff. To the right of the clef is the key signature. If the piece is written in the key of C major or A minor (no sharps or flats) then there will be no symbols indicated in the key signature. If the piece is written in any other key, the sharps or flats of that key will be indicated in the key signature. To the right of this (on the 1st musical staff) is where we find the time signature.

The top number of a time signature can be any number. This means that we can have any number of beats per measure in a piece of music. However, since most music tends to follow symmetrical rhythmic patterns most simple pieces contain either two, three, or four beats per measure. The most common time signatures contain a four on the bottom; and either a two, three or four on top. When there is an eight on the bottom of the time signature, the most common top number is six. However, more complex musical pieces can contain diverse rhythmic patterns. In these cases, other (less common) numbers are used on the top of the time signature. These types of time signatures will be discussed in more detail in future lessons.

The bottom number of a time signature can only be part of a sequence starting with 1 and continuing with the double of the number that precedes it. In other words, the numbers of this sequence are: 1, 2, 4, 8, 16, 32, 64, 128… and they continue on in this pattern. The reason for this specific sequence is the fact that each bottom number of a time signature corresponds to a note value (1 = whole note / 2 = half note / 4 = quarter note / 8 = eighth note / 16 = sixteenth note / 32 = thirty-second note …).

One method I use to help my students realize the value of the bottom number of a time signature involves the visualization of fractions. I have them convert the time signature into a fraction. Next, we discard the top number since we are only concerned with the value of the bottom number at the moment. We replace the top number (or numerator) of this imaginary fraction with a 1. The fraction that results from this process represents the name of the rhythmic value that receives one beat in this time signature. A fraction of ½ corresponds to the half note; a fraction of ¼ corresponds to the quarter note and so on.

The bottom number of a time signature can only be part of a sequence starting with 1 and continuing with the double of the number that precedes it. In other words, the numbers of this sequence are: 1, 2, 4, 8, 16, 32, 64, 128… and they continue on in this pattern. The reason for this specific sequence is the fact that each bottom number of a time signature corresponds to a note value (1 = whole note / 2 = half note / 4 = quarter note / 8 = eighth note / 16 = sixteenth note / 32 = thirty-second note …).

One method I use to help my students realize the value of the bottom number of a time signature involves the visualization of fractions. I have them convert the time signature into a fraction. Next, we discard the top number since we are only concerned with the value of the bottom number at the moment. We replace the top number (or numerator) of this imaginary fraction with a 1. The fraction that results from this process represents the name of the rhythmic value that receives one beat in this time signature. A fraction of ½ corresponds to the half note; a fraction of ¼ corresponds to the quarter note and so on.

In beginning music lessons most teachers tell their students that the quarter note receives one beat, the half note receives two beats, the whole note receives four beats and the eighth note receives half a beat. This information is correct if the bottom number of the time signature is a four. However, the actual beat values of each rhythm are not set throughout all musical examples. They change based on the bottom number of the time signature. What is set is the relative length of each rhythmic value in comparison with each other. A half note will always be half the value of a whole note. A quarter note will always be a quarter of the value of a whole note and half the value of a half note. Beginning music teachers tell the “white lie” of set rhythmic values because it is too difficult to explain the actual system of rhythmic values to a beginning music student (in most cases). Plus, most beginning music contains time signatures that have a four as the bottom number. Later on, when the student begins to experience time signatures with other numbers on the bottom, we explain the actual system of rhythmic values. In the video, I provide a chart that displays the rhythmic values of a whole, half, quarter and eighth note in time signatures that contain either a two, four or eight as the bottom number. This chart does not cover every rhythmic value under every type of time signature, but it displays enough values to illustrate the concept.

This Learning Music With Ray video discusses time signatures. In it, I discuss the location of the time signature in a piece of music and the information it provides for the reader. I point out the significance of the top and bottom numbers and explain the musical parameters covered by each number.