Pulse rate from a camera

This measures your heart rate from a webcam, with nothing touching you. Blood flowing through the skin of your face changes its colour by a fraction of a percent with every beat - far too little to see, but a camera can pick it out if you sit still in decent light.

How it works

Face tracking places sampling patches on your forehead and both cheeks, skipping hair, beard and glasses. The red, green and blue channels are combined so that changes caused by movement and lighting cancel out and the pulse survives. Fifteen seconds of that signal are then examined for the frequency that stands out.

What it will not tell you

Pulse rate only. Heart rate variability, rhythm and atrial fibrillation screening, and pulse transit time were all built and then removed: at 30 frames per second the timing of individual beats is too coarse to support them, and the earlier versions produced confident-looking numbers that were wrong.

When it fails

Movement, dim or uneven light, backlighting, and talking. It refuses to show a number rather than show a bad one, so a blank reading is normal and means the estimate was rejected. Expect to spend the first few seconds adjusting your position and light.

How accurate is it?

Checked against a Pixel Watch ECG recorded within a minute of each session. When the signal quality indicator is above its threshold the estimate landed within about 1 bpm of the ECG. When quality was marginal it was out by 3 bpm, while still looking perfectly confident on screen. That is from three sessions with one person - nowhere near enough to claim a general accuracy figure, and nothing here has been tested across different skin tones, ages, lighting setups or cameras.

This is an experiment, not a medical device. It is not a clinically validated instrument, it has not been reviewed or approved by anyone, and it must not be used to make any decision about your health. It cannot detect a heart condition and a normal-looking reading means nothing about your wellbeing. If you have any concern about your heart, or symptoms such as chest pain, breathlessness, palpitations or dizziness, contact a doctor or your local emergency service.

Video is processed entirely in your browser. No images and no measurements are uploaded or stored anywhere. Nothing leaves the page unless you press Log Data, which saves a file to your own device.

Live Feed

Camera off.

Pulse Rate (rPPG)

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Heart rate (bpm)HR bpm
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Dominant frequency of the POS pulse signal over a 15 s window, 0.7-3 Hz. Only shown when the signal quality gate passes - a blank reading means the estimate was not trustworthy, not that your heart stopped.
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Signal qualityQuality
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Share of 0.7-3 Hz band power sitting in the pulse peak and its second harmonic. Measured against a reference ECG, gating at 50% cut rate error from 11.0 to 2.6 bpm.
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Rate spread (bpm)Spread
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Standard deviation of accepted rate estimates over the last 60 s, sampled at least 7.5 s apart so the windows are largely independent. Low spread means the estimate is repeatable - it does not prove it is accurate.
Idle
StatusStatus
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On mobile this is shown over the camera instead, where you are already looking. Acquiring means the 15 s window is still filling; poor signal means the gate rejected it.

How to use it

Press Start Camera and allow camera access. Sit still, face a light source and avoid backlighting. The estimate needs a full 15 second window and only appears while signal quality clears 50%, so a blank reading means it was rejected as untrustworthy - not that nothing was detected.

Read the bar across the top of the video rather than this panel while measuring. Looking away moves your head, and head movement is the single biggest cause of a failed reading. Stillness on that bar is the number you can act on: on test recordings every window that stayed above roughly 60% cleared the quality gate, and everything below 45% failed.