Why does helium change your voice? The science explained

Breathe in from a party balloon and your voice goes high and squeaky for a few seconds. Everyone has heard it, but the usual explanation ("helium raises your pitch") is wrong. Here is what helium actually does to your voice, and how to get the same effect without inhaling any gas.

What does helium do to your voice?

Helium makes your voice sound higher and thinner, but it does not change the pitch your vocal cords produce. Two different things are at work, and only one of them moves.

Pitch vs resonance

Your pitch is set by how fast your vocal cords vibrate. That rate barely changes in helium, so the fundamental note you sing or speak stays almost the same.

What changes is resonance. Above your vocal cords sits a tube of air (your throat, mouth and nose) that acts like a little instrument, emphasising certain frequencies called formants. Sound travels roughly three times faster in helium than in ordinary air, and faster sound in the same sized cavity pushes those formants upward. Lift the formants and the voice sounds bright, thin and cartoonish, even though the underlying pitch has hardly moved. That is why helium changes your voice but not really your pitch.

Why it sounds squeaky, in one line

Same vocal-cord pitch, higher resonances. Your brain reads the raised formants as a smaller, lighter voice, so it sounds like a chipmunk or a cartoon character.

Important: do not inhale helium

The squeaky trick is fun, but inhaling helium is not safe. Helium displaces the oxygen in your lungs, which can cause dizziness, fainting, and in serious cases asphyxiation. Helium straight from a pressurized tank can also injure your lungs. There is no safe amount worth the risk when you can get the exact same sound from an app.

Get the helium voice safely

A helium voice changer recreates the effect by lifting the resonances of a recording, the same shift helium causes, with nothing to breathe. With Reverse Audio on iOS and Android:

• 1. Record or import a clip. Capture your voice live or pull in an existing file.
• 2. Tap the Helium preset. The app raises the resonances to mimic the helium sound.
• 3. Save or share. Keep it or send it on, all on your device.

Want it even higher and faster? Try the chipmunk voice changer, or compare every pitch-up option on the high pitched voice changer page. For the opposite, drop low with the deep voice changer.

The short version

Helium does not raise your pitch, it speeds up sound in your vocal tract and lifts your voice's resonances, so you sound squeaky. It is a fun effect and a bad gas to inhale, so get the sound from a voice changer instead.