Time signature
A time signature is the pair of numbers at the start of a piece. The top number is how many beats are in each measure; the bottom number is which note gets one beat. 4/4 means four quarter-note beats to a measure, and is often written as a C, called common time.
How to read it
The bottom number names a note by its fraction of a whole note: 4 for a quarter note, 2 for a half note, 8 for an eighth note. So 3/4 is three quarter-note beats to the measure and 6/8 six eighth-note beats. The C sign stands for 4/4, and a C with a vertical stroke through it (cut time, or alla breve) for 2/2. The time signature comes immediately after the key signature, and is written again only where the time changes.
Also searched as: common time, meter.
Is the C a letter?
Evans’s Primer (1909) calls the common-time sign “the letter C”. Gehrkens (1914) disagreed: it is not a letter C but a broken circle. In medieval measured music, he explains, a full circle meant three beats to the measure, then called perfect time, and a broken circle two. The circle dropped out of use; the broken circle survives as the C and the cut C.
What it doesn’t say
A time signature gives the number and kind of beats, not the speed. Stainer and Barrett’s dictionary (1898) suggests “measure-sign” would be a better name for that reason. The speed is given separately, by Italian words such as allegro and andante.
Read next
- Next in Music symbolsSharpA sharp raises a note by a half step (a semitone). F sharp is the note a half step above F.
- The same shape in Smoke and CO alarm soundsLow-frequency 520 Hz alarm (sleeping rooms)A fire alarm in a sleeping room that sounds a low buzz in place of a high-pitched beep. It is the three-beep fire alarm rhythm at 520 Hz, which NFPA 72 requires of alarms provided to wake people in sleeping areas.
More music symbols
The same shape elsewhere
Browse symbols drawn with letters and numbers or lines.
Sources
- Music Theory for the 21st-Century Classroom: Time Signature, Robert Hutchinson, section 4.1, University of Puget Sound, Section 4.1
- Music Theory for the 21st-Century Classroom: Durational Symbols, Robert Hutchinson, section 4.2, University of Puget Sound, Section 4.2
- Primer of Facts about Music, M. G. Evans, 1909, Theodore Presser Co. (Internet Archive, University of Toronto), Q. 31
- Music Notation and Terminology, Karl W. Gehrkens, 1914, A. S. Barnes Company (Project Gutenberg), Chapter X, §103; Appendix A
- Stainer and Barrett's Dictionary of Musical Terms, John Stainer and W. A. Barrett, new and revised edition, 1898, Novello (Internet Archive, Cornell University Library), Signature
Researched, edited and approved by Rory Hansen before publishing. Last reviewed September 26, 2026. How we research
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