Listen to 113 frequencies
From 20 Hz to 24 kHz — pick a frequency and hear it right away, with its wavelength, period and nearest musical note worked out for you.
Turn the volume down before you play. A pure tone is harder on the ears than music at the same level.
Infrasound (below 20 Hz)3
Bass (20–250 Hz)27
Midrange (250 Hz–4 kHz)50
Treble (4–20 kHz)29
Ultrasound (above 20 kHz)4
How to read this
- Hertz counts how many times the air vibrates per second. The bigger the number, the higher the pitch.
- Wavelength is the speed of sound (343 m/s at 20 °C) divided by the frequency. That makes 20 Hz seventeen metres long and 20 kHz under two centimetres.
- People hear roughly 20 Hz to 20 kHz, but the upper limit drops with age. Past about 15 kHz, some hear the tone and some do not.
- Hearing nothing does not mean the equipment is broken. Small speakers cannot reach the low notes, and for the high ones it is the ear that gives up first.
Frequently asked questions
Q. What frequencies can people hear?
Roughly 20 Hz to 20 kHz. The upper limit falls with age, though: someone who heard 18 kHz at twenty often stops around 14 kHz by forty. At the bottom end, 20 Hz is felt in the body more than heard.
Q. I hear nothing — are my speakers broken?
Probably not. The small speakers in a laptop or phone barely produce anything below 100 Hz, and above 15 kHz it is your ears, not the hardware, that run out first. Trying headphones usually settles which it is.
Q. Is it safe to listen to a pure tone for a while?
Keep the volume low and the sessions short. A pure tone concentrates all its energy at one frequency, so it strains the ear more than music at the same level. If your ears feel dull or ring afterwards, stop.
Q. What is the difference between 440 Hz and 432 Hz?
Both are an A, but 432 Hz sits 32 cents below 440 Hz — about a third of a semitone, clearly audible side by side. The international standard is 440 Hz; claims that 432 Hz is somehow better have no evidence behind them.
Q. How are these numbers worked out?
Only the frequency itself is stored. Wavelength is the speed of sound in 20 °C air, 343 m/s, divided by the frequency; the note name comes from taking 440 Hz as A4 and the fact that one semitone is the twelfth root of two.