#### 3.3.5 Time signature

Time signature indicates the metrum of a piece: a regular pattern of strong and weak beats. It is denoted by a fraction at the start of the staff.

The time signature is set or changed by the `\time` command

>          \time 2/4 c'2 \time 3/4 c'2.

The symbol that is printed can be customized with the `style` property. Setting it to `#'()` uses fraction style for 4/4 and 2/2 time. There are many more options for its layout. See input/test/time.ly for more examples.

This command sets the property `timeSignatureFraction`, `beatLength` and `measureLength` in the `Timing` context, which is normally aliased to Score. The property `measureLength` determines where bar lines should be inserted, and how automatic beams should be generated. Changing the value of `timeSignatureFraction` also causes the symbol to be printed.

More options are available through the Scheme function `set-time-signature`. In combination with the Measure_grouping_engraver, it will create MeasureGrouping signs. Such signs ease reading rhythmically complex modern music. In the following example, the 9/8 measure is subdivided in 2, 2, 2 and 3. This is passed to `set-time-signature` as the third argument `(2 2 2 3)`

>          \score {
>            \notes \relative c'' {
>              #(set-time-signature 9 8 '(2 2 2 3))
>              g8[ g] d[ d] g[ g] a8[( bes g]) |
>              #(set-time-signature 5 8 '(3 2))
>              a4. g4
>            }
>            \paper {
>              \context {
>                \StaffContext
>                \consists "Measure_grouping_engraver"
>              }
>            }
>          }

##### See also

Program reference: TimeSignature, and Timing_engraver.

##### Bugs

Automatic beaming does not use the measure grouping specified with `set-time-signature`.

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