Alto Flute Tuner — Free Online G Alto Flute Tuner

An alto flute is in G — written C sounds concert G a fourth below — and it is the only member of the flute family a tuner has to be told about. It is also hungrier than a C flute: a breath that fills a concert flute leaves an alto flat, so the reading that drops as a session goes on is your air, not your headjoint.

Tap “Start Tuning” and allow microphone access — audio is analyzed on your device and never leaves it. No microphone? You can still play reference tones for every note.

The one flute that transposes

A concert flute reads at concert pitch. A piccolo reads at concert pitch an octave down, so the letters still agree. The alto flute is in G — it sounds a perfect fourth below the page — and it is the only member of the family that genuinely needs a tuner to be told about it.

Written C comes out as concert G4, 392 Hz. When the orchestra tunes to concert A, your note is written D.

Try itAlto flute — written note to concert pitch

Concert pitch in the tone, the written note that produces it in the label. The highlighted row is the orchestral A.

The headjoint works the same; your air does not

Mechanically nothing has changed from a concert flute. The headjoint slides in and out of the body, out is flat and in is sharp, and the cork position at the crown sets the octave relationships. The only adjustment to how you do it is one of scale: the alto is a longer instrument, so the same millimetre buys fewer cents and you will move the headjoint further than you are used to.

The real difference is not mechanical at all. An alto flute needs substantially more air than a C flute, and it converts a shortage of air directly into flatness. A concert flute played on tired breath sounds thin; an alto flute played on tired breath sounds flat, which is the same problem presenting as a tuning fault.

The routine

Warm the instrument through. A long tube of cold metal plays flat, and the alto has more of it than a concert flute.
Play written D, mezzo-forte, with full support. At the dynamic and support level you actually perform at — not gently. Watch for concert A on the dial.
Sharp: pull the headjoint out. Flat: push it in. Expect to move it further than on a C flute for the same result.
Check the octaves. Written C4 against written C5. If the upper octave is sharp against the lower, the cork at the crown has drifted — that is a cork problem, not a headjoint one, and no amount of pulling will fix it.
Play a slow scale and watch which notes your embouchure bends. On an alto the low register is where support shows first: if written C4 through F4 read flat while the middle is centred, that is air.

Make the dial read your written note instead

Everything above names the concert pitch actually in the air, which is what a tuner is for and what the rest of the ensemble hears. But it is not what is printed on your part: a G alto flute sounds a perfect fourth lower than it reads, so written C comes out as concert G.

This tuner can close that gap for you. The Transposition setting adds the interval back before the note is named, so the dial reports the note you are reading rather than the note you are sounding — the one thing a guitar tuner has no reason to do, and the reason to keep this page rather than the first tuner in the results.

Open this tuner set to G → — or reach it yourself from the gear icon on the dial, under Transposition. The choice is remembered on this device and it travels in the link, so a section leader can send that URL to a stand full of alto flutes and everyone arrives set the same way.

Switch it back to C — Concert pitch whenever you need to check yourself against the room, tune to a piano, or find out what a written note is actually sounding.

The flute family, on the dial

Instrument	Key	Written C sounds	Does the dial match your part?
Piccolo	C	an octave higher	letter yes, octave no
Concert flute	C	at concert pitch	exactly
Alto flute (this page)	G	a perfect 4th lower	no — set Transposition to G

A bass flute, where you meet one, is in C and sounds an octave below the concert flute — so it behaves like the piccolo row of that table rather than this one.

Frequently asked questions

Does an alto flute transpose?

Yes, and it is the only flute in common use that does. It is in G and sounds a perfect fourth below what it reads, so written C is concert G4 at 392 Hz. A concert flute and a piccolo both read at concert pitch — the piccolo an octave up, but with the same letter — which is why flute players are rarely prepared for this one.

Why does my alto flute go flat as a rehearsal goes on?

Air. The tube is longer and wider than a concert flute’s, so it needs more air to fill and more support to keep the pitch up — and as you tire, the support goes first. A concert flute punishes a tiring player with a thin tone; an alto flute punishes them with flatness. If the dial drifts downward over twenty minutes and the headjoint has not moved, that is your breath rather than your instrument.

Straight or curved headjoint — does it affect the pitch?

Not the pitch, but potentially the player. Both are cut to the same acoustic length, so the instrument tunes identically either way. A curved headjoint brings the instrument closer and makes it easier to support, which in practice can mean a curved-head player holds pitch better simply because they are not fighting the reach.

How do I tune it — is it the headjoint like a concert flute?

Yes. Pull the headjoint out of the body to flatten, push it in to sharpen, exactly as on a C flute. The difference is scale: the alto is longer, so a given millimetre is a smaller proportion of the instrument and moves the pitch less. Expect to move it further than you would on a concert flute for the same correction.

What do I play when the orchestra tunes to concert A?

Written D. Sounding a fourth below written pitch, your D becomes concert A4 at 440 Hz. For a concert B♭ call in a band setting, play written F.