Music Clefs Explained: Treble, Bass, Alto & More

A clef is the symbol at the start of a staff that fixes which pitch sits on each line and space. Change the clef and the same written note becomes a different pitch, which is why a cellist and a flutist can read parts that look alike on the page but sound far apart. Clefs exist so that instruments in very different ranges can stay on the staff instead of drowning in ledger lines. This guide covers the treble, bass, alto, and tenor clefs, the instruments that read them, the less common octave and percussion clefs, and how to add or change a clef in Flat.

What is a clef, and why are there several?

The five lines and four spaces of a staff carry no pitch on their own. The clef is what assigns them: put a treble clef on a blank staff and the second line from the bottom is G, but put a bass clef on the same staff and that line becomes a different note. That is why the clef comes first on every staff, before the key signature and time signature. Until you know the clef, nothing on the lines and spaces can be read.

The reason there is more than one clef is range. A single clef would force a low instrument like the double bass under a tall stack of ledger lines and a high one like the piccolo to float above another. Each clef shifts the staff to a different part of the range so that an instrument's notes land on or near the lines, where they are quick to read. If you are still getting comfortable with note names, our guide to reading notes on the staff pairs well with this one.

Treble and bass clef, the two you will see most

The treble clef is also called the G clef. Its curl circles the second line from the bottom, marking that line as the G above middle C. Reading up the lines from there gives E, G, B, D, F (the old mnemonic is "Every Good Boy Does Fine") and the spaces spell F, A, C, E. Violin, flute, oboe, trumpet, guitar, and the right hand of the piano all read treble clef, along with higher voices.

The bass clef is the F clef. Its two dots sit above and below the fourth line, marking it as the F below middle C. The lines read G, B, D, F, A ("Good Boys Do Fine Always") and the spaces A, C, E, G ("All Cows Eat Grass"). Cello, double bass, bassoon, trombone, tuba, and the left hand of the piano read bass clef, along with lower voices.

In piano and other keyboard music the two are joined into a grand staff, treble on top and bass below, with middle C sitting on a short ledger line between them. Together they span almost the whole instrument without ledger-line pileups. Here are the four clefs you will actually meet, and who reads them:

Clef	Type	Fixes	Mainly read by
Treble	G clef	G above middle C, on line 2	Violin, flute, oboe, trumpet, guitar, right hand of piano, higher voices
Bass	F clef	F below middle C, on line 4	Cello, double bass, bassoon, trombone, tuba, left hand of piano, lower voices
Alto	C clef	Middle C, on the middle line	Viola
Tenor	C clef	Middle C, on line 4	High passages of cello, bassoon, and trombone

The C clefs: alto and the viola

The alto and tenor clefs are both C clefs: the center of the symbol points at middle C, wherever it is placed. In the alto clef, middle C sits on the middle line of the staff. That one choice is what makes the alto clef useful for the viola, whose range sits right between the violin and the cello. Written in treble clef the viola's low notes would need ledger lines below the staff; written in bass clef its high notes would need ledger lines above. Centering middle C keeps most of the part on the staff.

The viola is the one common instrument that reads alto clef as its home clef. Telemann's Viola Concerto in G major is a good place to hear the instrument on its own rather than doubling other strings, with the solo part written throughout in alto clef.

When the clef changes mid-part: the tenor clef

The tenor clef is the other C clef, with middle C on the second line from the top. It solves a problem inside a single part: instruments whose home is the bass clef, like the cello, bassoon, and trombone, sometimes climb high enough that bass clef would stack ledger line after ledger line above the staff. When that happens the part switches to tenor clef (and, higher still, to treble) for those passages, then drops back to bass clef. A clef can change at any point in a piece, not only at the beginning.

Bach's Cello Suites are a clear example. Five of the six stay in bass clef from start to finish, but Suite No. 6, written for an instrument with a fifth, higher string, climbs far enough that the part moves up into tenor and treble clef to stay readable.

Other clefs: octave and percussion

A few other clefs turn up in specific situations. An octave clef is an ordinary clef with a small 8 attached: a treble clef with an 8 below it sounds an octave lower than written, and is used for guitar and for the tenor voice, which would otherwise sit on a forest of ledger lines. The percussion clef, also called the neutral clef, is a pair of vertical lines used for unpitched instruments such as a drum kit, where each line and space stands for an instrument rather than a pitch. Older music also used soprano, mezzo-soprano, and baritone C clefs, but those are rare in modern scores.

How to add or change a clef in Flat

In Flat, the clef is set for you when you pick an instrument, so a cello part opens in bass clef and a violin part in treble. To change it, click the clef at the start of the staff and choose a new one, or use the clef tool in the "Measure" toolbar to insert a clef change partway through a part.

Try this in Flat: open a new score, enter a short phrase that climbs above the staff in bass clef until it sits on three or four ledger lines, then insert a tenor clef at that bar and watch the same notes drop back onto the staff. The pitches do not change, only the way they are written. For the steps in full, see the help guide on adding or changing a clef.

Bringing it together

A clef is a small symbol doing a big job: it decides what every line and space means. Treble and bass cover most of what you will read, the grand staff joins them for keyboard music, and the alto and tenor C clefs keep the viola and the high reaches of the cello, bassoon, and trombone on the staff instead of buried in ledger lines. Once you can recognize a clef and the reference note it fixes, you can read any staff in front of you.

Ready to write your first multi-clef score? Flat lets you pick an instrument, switch clefs anywhere in a part, and hear it play back in your browser, no download needed. Try Flat for free.