Binaural beat calculator.
A binaural beat is a subtraction: play 200 Hz in one ear and 210 Hz in the other, and what you perceive is a 10 Hz pulse that exists nowhere in the air. This calculator works that sum in both directions — give it a target beat and it returns the two ear tones, or give it two tones and it returns the beat, the carrier midpoint and the brainwave band they land in. Then, unlike every other calculator on this subject, it plays them.
0–40 Hz. This is the rhythm you are aiming for.
60–1000 Hz. The pitch you actually hear.
Enter the two tones and the calculator returns their difference — the beat — and the midpoint carrier.
Headphones required to hear a binaural beat. The calculator will happily play on a speaker, but the two tones will mix in the air and you will hear a plain wobble instead. Sessions here stop after 20 minutes, like the rest of the free tools. Set the volume low — a sine wave is more fatiguing than it sounds.
The formula, in one line.
Beat frequency = the difference between the two ear tones. Carrier = their midpoint. That is the entire calculation, and everything else on this page is a consequence of it.
Written out: if your left ear receives fL and your right ear receives fR, the beat you perceive is |fR − fL| and the pitch you perceive is (fL + fR) / 2. Going the other way, for a target beat b around a carrier c, the two tones are c − b/2 and c + b/2. Splitting the beat evenly around the carrier is a convention, not a rule — 200/210 and 195/205 both produce a 10 Hz beat — but it keeps the perceived pitch where you put it.
Which ear gets the higher tone does not matter for the beat itself; the difference is what counts. Some protocols deliberately alternate the sides between sessions, and there is no good evidence that it changes the outcome.
| You know | You want | Calculation |
|---|---|---|
| Beat + carrier | The two ear tones | carrier − beat/2 and carrier + beat/2 |
| Two ear tones | The beat | the difference between them |
| Two ear tones | The carrier | their midpoint |
| Beat + one tone | The other tone | add or subtract the beat |
Which numbers actually work.
Keep the beat under about 30 Hz and both tones under about 1000 Hz. Outside those bounds the perception breaks down — not because the arithmetic fails, but because the auditory system stops fusing the two tones into one beating image.
The constraint comes from how the beat is produced. It is not an acoustic interference pattern; it is computed in the superior olivary complex from the timing difference between the two ears, and that timing comparison works on the phase of the waveform. Above roughly 1000 Hz the auditory nerve can no longer lock to individual cycles, so there is no reliable phase information left to compare and the beat fades. Oster’s 1973 Scientific American account is still the clearest description of this, and it is where the commonly cited limits come from.
At the other end, a difference much above 30 Hz stops being heard as one tone pulsing and starts being heard as two separate pitches. That is why this calculator’s player, and the main generator, both cap the beat at 40 Hz and the carrier between 60 and 1000 Hz — the 40 Hz ceiling exists because gamma protocols ask for it, not because 40 Hz is comfortable.
| Parameter | Workable range | Why |
|---|---|---|
| Carrier | Roughly 100–500 Hz is the comfortable zone; the effect survives to about 1000 Hz | Phase-locking in the auditory nerve degrades as pitch rises, and the beat degrades with it |
| Beat | 1–30 Hz reliably; up to 40 Hz for gamma protocols | Beyond that the tones separate into two audible pitches |
| Beat of 0 | Valid, but it is a pure tone | Identical tones in both ears produce no difference to perceive |
| Volume | Low. Quieter than music | Sine waves are fatiguing, and louder does not make the beat stronger |
A low carrier is usually the more comfortable choice for a long session: 100–200 Hz sits under the ear’s most sensitive region, so it is easier to leave running for twenty minutes. Very low carriers have the opposite problem — below about 60 Hz many headphones simply do not reproduce a clean sine.
What the band names mean.
Delta, theta, alpha, beta and gamma are names for ranges of EEG activity, not names for what a sound does to you. The calculator labels your beat with the band it falls in because that is the vocabulary everyone uses — but the label describes a measured brain rhythm, not a promised outcome.
| Band | Range | What EEG associates it with | Play a typical value |
|---|---|---|---|
| Delta | 0.5–4 Hz | Deep, slow-wave sleep | 2 Hz → |
| Theta | 4–8 Hz | Drowsiness, deep relaxation, meditation | 6 Hz → |
| Alpha | 8–12 Hz | Relaxed, eyes-closed wakefulness | 10 Hz → |
| Beta | 12–30 Hz | Alert, active, externally directed thinking | 18 Hz → |
| Gamma | 30 Hz and up | Demanding cognitive work, feature binding | 40 Hz → |
The step people skip is the one that matters: your EEG has an alpha rhythm and listening to a 10 Hz beat puts your EEG into that rhythm are two different claims, and only the first is settled. EEG studies do consistently find a frequency-following response to binaural beats, but how far that response translates into a felt change is small, variable between people, and inconsistent across trials. The research hub lists the studies with their sample sizes, including the ones that found nothing. If you want the longer version of the band vocabulary, brainwave frequencies explained covers it.
Three worked examples.
If you would rather copy a set of numbers than reason about them, start with one of these. Each is a real preset from the generator, written out the long way.
- A 2 Hz delta beat for sleep, on a 100 Hz carrier. Left ear 99 Hz, right ear 101 Hz. The low carrier is deliberate — it is unobtrusive enough to fall asleep to. Play it →
- A 10 Hz alpha beat for reading, on a 200 Hz carrier. Left ear 195 Hz, right ear 205 Hz. This is the default in the box above and the safest first thing to try. Play it →
- A 40 Hz gamma beat, on a 300 Hz carrier. Left ear 280 Hz, right ear 320 Hz. Note how wide that split is — at 40 Hz you may hear two pitches rather than one pulsing tone, which is the upper limit doing exactly what § 02 describes. Play it →
Going the other way is the more common real use: you found a track described as “432 Hz and 440 Hz binaural” and want to know what it actually is. Put those two into the second tab and you get an 8 Hz beat on a 436 Hz carrier — an alpha-band beat, with a carrier high enough that the effect will be weaker than the same beat at 200 Hz. That is the kind of thing the label on the track never tells you.
Things people reasonably ask.
What is the formula for a binaural beat?
The beat is the difference between the two tones and the carrier is their midpoint. For a target beat b on a carrier c, play c − b/2 in one ear and c + b/2 in the other. A 10 Hz beat on a 200 Hz carrier is 195 Hz and 205 Hz.
Does it matter which ear gets the higher frequency?
No. The beat depends on the size of the difference, not its direction. Some protocols alternate the sides between sessions; there is no good evidence that this changes anything.
What is the best carrier frequency?
Whichever is most comfortable to listen to for as long as you plan to listen. Between 100 and 200 Hz is the usual recommendation because it sits below the ear’s most sensitive range and stays unobtrusive. The effect is thought to weaken as the carrier rises past roughly 1000 Hz, because the auditory nerve can no longer phase-lock to individual cycles.
Can the beat frequency be higher than 40 Hz?
Arithmetically yes, perceptually not usefully. Above about 30 Hz the two tones increasingly separate into two audible pitches rather than fusing into one pulsing tone. This calculator and the generator both stop at 40 Hz, which is as high as the gamma protocols ask for.
Why do I need headphones for this?
Because the beat is not in the sound. It is produced by your brainstem comparing what arrives at each ear, so each ear has to receive its own tone. On a speaker the two tones mix in the air before they reach you and what you hear is ordinary acoustic beating — a wobble, not a binaural beat. If you have no headphones, the isochronic mode gives you a rhythm that works on speakers.
What happens if I set the beat to zero?
You get a pure tone. Both ears receive the same frequency, there is no difference to perceive, and the generator switches to pure-tone mode automatically. That is a legitimate thing to want — see the pure tone generator.
Is a calculated beat different from a preset?
No. The presets in the generator are just named pairs of these numbers. Calculating your own is useful when you want a value between the presets, or when you are trying to work out what some track you found is actually playing.
Do binaural beats work at any of these frequencies?
The honest answer is: modestly, inconsistently, and not for everyone. The strongest pooled result is a small-to-moderate effect on in-the-moment anxiety across 22 studies. Effects on attention, memory and sleep come from smaller trials with mixed findings. Nothing about picking a more precise number changes that — see the research hub.