How to use ECG on Apple Watch: record a clean reading

Starting an ECG takes two steps

Open the ECG app on your watch, the red heartbeat with a waveform running through it:

The ECG app on the watch home screen: the red heartbeat with a waveform.

Then rest a finger from your opposite hand lightly on the Digital Crown: no need to press. The 30-second recording starts as soon as contact is made:

The ECG app prompts you to hold your finger on the crown, touch lightly, and the countdown begins.

That's the whole idea. The rest of this guide covers the two things that trip people up, a missing ECG app, and noisy recordings, plus when to record for the most useful result.

Can't find the ECG app?

Not every Apple Watch has ECG. If the app is missing, this is by far the most common reason, not anything you did wrong. You'll need:

• Apple Watch Series 4 or later, or any Apple Watch Ultra. The Apple Watch SE has no ECG sensor: it's a hardware difference, so no software update can add it.
• A paired iPhone 8 or later running a recent version of iOS, with the ECG app set up once via the Health app.
• A supported country or region: ECG availability varies by location, and your iPhone's region setting must match one where it's offered.
• Age 22 or older: Apple requires this to enable the ECG app.

If your model qualifies but the app still doesn't appear, the one-time setup below usually fixes it.

Setting up the ECG app (one-time)

1. Update both devices: install the latest iOS on your iPhone, then open the Watch app → General → Software Update for watchOS. Out-of-date software is the most common setup blocker.
2. Open the Health app on your iPhone and go to Browse → Heart → Electrocardiogram (ECG).
3. Tap "Set Up the ECG App" and follow the on-screen instructions.
4. Check your watch: the ECG app should now appear, ready to use.

For the full walkthrough, compatibility checks, your first reading, and fixes if the app still won't appear, see How to set up the ECG app on Apple Watch.

Clean recording, step by step

1. Sit down and rest your arms on a table or your lap.
2. Dry your wrist and the watch. This matters most of all, moisture weakens the electrical signal.
3. Check the fit: snug on your wrist, not squeezed tight.
4. Take a few slow, deep breaths. Feeling a little anxious is completely normal, especially if you're recording because you felt something. The breaths settle you, your arms and the recording.
5. Open the ECG app: the red heartbeat with a waveform.
6. Rest a finger lightly on the Digital Crown. No need to press; the countdown starts on contact.
7. Stay still for 30 seconds, breathing slowly, without talking or moving.
8. Save the result, adding any symptoms you felt, palpitations, a skipped beat, dizziness. The recording syncs to the Health app on your iPhone automatically, where ECG+ can analyze it in detail.

Tips for the cleanest recording

Dry skin contact comes first. A damp wrist, from washing your hands, sweat, or lotion, is the single most common cause of a poor recording. A few seconds with a towel before you start makes more difference than anything else.

Hold the watch with two fingers. Even tiny finger movements or pressure changes on the crown disturb the signal. Index finger on the crown, thumb on the corner of the watch body, both the finger and the pressure stay steady:

The two-finger hold: index finger on the crown, thumb on the corner, steady contact, steady pressure.

Rest both arms on a table. Arms supported and relaxed, not held in the air, keep the natural shakiness of the muscles out of the waveform:

Arms rested and relaxed: the easiest way to keep muscle noise out of your recording.

Get the fit just right. A loose watch loses skin contact; an overtight band can distort the signal too. Snug and comfortable is the goal:

Snug, not tight: steady skin contact without squeezing the wrist.

If it says "Poor Recording" or "Inconclusive"

Don't be alarmed, this says nothing about your heart. It means the watch couldn't read a clean enough signal: a damp wrist, a small movement, a loose band. Dry your wrist, take a few slow breaths, and record again, most people get a clear reading on the next try. If it keeps happening, see our guides to fixing a "poor recording" and what "inconclusive" means.

When should you record?

The moment you feel something. A skipped beat, a flutter, a racing heart, symptoms rarely wait for a doctor's appointment, and a recording taken during the symptom is the most valuable one you can capture. Since the watch is already on your wrist, a 30-second recording right then can hold the answer.

Recording when you feel perfectly fine is useful too: it gives you a healthy baseline for comparison, and regular readings build up your HRV and heart-rate trends over time.

Getting more from every recording

The built-in app classifies your rhythm, sinus rhythm, AFib, or inconclusive, and stops there. ECG+ reads the same recording for the detail the watch leaves out: every heartbeat annotated with its timing, possible premature beats (PACs and PVCs) marked where they happen, rhythm patterns, QT/QTc and HRV, all in a report you can share with your doctor.