To use ECG on Apple Watch, you need an Apple Watch Series 4 or later or any Apple Watch Ultra, current compatible software, and a region where Apple has enabled the feature. Apple Watch SE does not support the ECG app, and Apple says the app is not intended for people under 22. Update the paired iPhone and watch to their latest software; Apple’s current support article does not specify a stable minimum iPhone model.
Once set up, the ECG app records a 30-second, single-channel electrical tracing similar to a clinical Lead I ECG. It classifies supported recordings, but it is not a 12-lead ECG, does not continuously monitor for AFib, and cannot rule out a heart attack or other medical emergency.
Before you start: check compatibility
| Requirement | What you need |
|---|---|
| Apple Watch | Apple Watch Series 4 or later, or any Apple Watch Ultra |
| Unsupported model | Apple Watch SE does not support the ECG app |
| Paired iPhone | Update the iPhone to the latest compatible iOS; Apple’s current ECG support article does not state a stable minimum iPhone model |
| Software | Latest compatible versions of iOS and watchOS |
| Region | ECG must be available in your country or region; availability and app version may vary |
| Age | Apple says the ECG app is not intended for people under 22 |
Model compatibility alone is not enough. Apple’s health features vary by country or region and can change as regulatory authorization changes. Check regional availability and update both devices. To check the ECG app version, use Watch Settings > Heart > ECG, or on iPhone use Health > Browse > Heart > ECG > About.
If you are shopping for a watch because your current one is an SE or another unsupported model, compare Apple Watch with ECG models only after confirming regional availability and software compatibility. Buying an ECG-capable watch is not a medical treatment decision; it simply makes the feature available when the other prerequisites are met.
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Prepare the iPhone and Apple Watch
- Pair the Apple Watch with a compatible iPhone.
- Install available iOS updates on the iPhone and watchOS updates on the Apple Watch.
- Confirm which wrist the watch is set to use. On the iPhone, open the Watch app, select My Watch, then go to General > Watch Orientation. Wear the watch on the selected wrist.
- Charge the watch sufficiently so it will not shut down during setup or recording. A charger is convenient but not part of ECG installation.
The ECG app uses the electrical heart sensor on the back of the watch and the Digital Crown. There is no separate sensor or hardware installation process.
How to set up the ECG app
Setup takes place in the Health app on the paired iPhone.
- Open Health on the iPhone and follow the ECG setup prompt if it appears.
- If no prompt appears, choose Browse > Heart > Electrocardiograms (ECG).
- Tap Set Up ECG App.
- Read the information screens and complete the requested details.
- When setup finishes, open the ECG app on the Apple Watch.
If the ECG app is not on the watch after onboarding, open the iPhone’s Watch app, choose Heart, and install ECG if offered.
If setup is unavailable, recheck the watch model, regional availability, age guidance, pairing status, and software updates. Do not assume that a missing app means the watch hardware is defective.
How to record an ECG correctly
Take the recording while seated and resting—not during exercise.
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- A POWERFUL FITNESS TRACKER—With advanced metrics and motivating features like Pacer, Heart Rate Zones, training load, and Workout Buddy powered by Apple Intelligence from your nearby iPhone*—Series 11 is made to help everyone stay active, from runners and hikers to strength-training enthusiasts.
- Wear the watch snugly on the selected wrist, with its back making consistent contact with the skin.
- Rest the arm wearing the watch on a table or in your lap and try to stay still.
- Open the ECG app on the Apple Watch.
- With the opposite hand, touch one finger to the Digital Crown. Do not press it.
- Keep still and maintain contact for the entire 30-second recording.
- When prompted, add any useful symptom notes and save the result.
For the best chance of a readable signal, keep the watch and wrist clean and dry. Water, sweat, movement, a loose band, and electrical interference can contribute to a poor recording. After swimming, showering, heavy perspiration, or washing your hands, clean and dry the watch; Apple says complete drying can take an hour or more. Move away from plugged-in electronics if you suspect interference.
The watch records a single electrical channel comparable to Lead I. It is useful for capturing a rhythm snapshot, but it is not equivalent to the multi-lead ECG equipment commonly used in a clinic.
What the ECG results mean
| Result or version detail | What it means | Important limit |
|---|---|---|
| Sinus rhythm | The recording showed a uniform pattern in the app’s supported range, generally 50–100 BPM. | It describes that recording only; it does not prove overall heart health. |
| AFib | The recording showed an irregular pattern consistent with atrial fibrillation. | If you have not previously been diagnosed with AFib, discuss the result with a doctor. |
| Inconclusive or poor recording | The app could not classify the tracing, or the rate or signal was outside supported conditions. | It does not necessarily mean the rhythm is abnormal. |
| Version 1 range | AFib classification range: 50–120 BPM. | A non-AFib recording at 100–120 BPM may be classified as inconclusive. |
| Version 2 range | AFib classification range: 50–150 BPM. A non-AFib recording from 100–150 BPM may be classified as high heart rate. | Rates outside the applicable range can limit classification. |
Sinus rhythm
A sinus-rhythm classification means the particular recording showed a uniform pattern within the app’s supported range. It is a statement about that recording only. It cannot rule out intermittent symptoms, disease, or a rhythm change before or after the recording.
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AFib
An AFib classification means the app detected an irregular pattern consistent with atrial fibrillation. Treat it as a reason to seek appropriate clinical advice, especially if AFib has never been diagnosed before. Do not use the watch result by itself to start, stop, or change medication.
Inconclusive or poor recording
The app may fail to classify a tracing because you moved, the watch was loose, the skin or watch was wet, electrical interference affected the signal, or the signal was insufficient. A pacemaker or ICD, or a rhythm or condition the app is not designed to recognize, may also result in an inconclusive reading. “Poor Recording” is a version 2 classification.
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The supported AFib heart-rate range depends on ECG app version: version 1 checks between 50 and 120 BPM, while version 2 checks between 50 and 150 BPM. Check your installed version rather than relying on a single threshold quoted in older advice.
How to fix a poor ECG recording
Work through this checklist rather than repeatedly recording while moving or exercising:
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- Return to the iPhone Health app and confirm ECG onboarding is complete.
- Clean and dry the back of the watch and your wrist.
- Adjust the band so the watch stays in steady contact without being uncomfortable. If your existing band cannot hold the watch securely, an Apple Watch replacement band may be a practical fit accessory, but no band guarantees a usable ECG or improves medical accuracy.
- Check Watch app > My Watch > General > Watch Orientation and verify that the selected wrist matches the wrist you are wearing the watch on.
- Sit down, rest your arm, stop talking, and touch the Digital Crown without pressing it.
- Move away from electrical devices connected to an outlet if you suspect interference.
- Repeat the recording only while resting. Do not take the ECG during exercise.
If repeated recordings remain poor despite correct fit, dry skin, stillness, and correct orientation, save the result if possible and discuss it with Apple Support or a clinician rather than trying to interpret an unclassifiable trace yourself.
How to view and share an ECG PDF
- Open the Health app on the iPhone or iPad.
- Choose Browse, then select Heart and Electrocardiograms (ECG).
- Open the recording you want to review.
- Choose Export a PDF for Your Doctor.
- Share or print the PDF for your clinician through an appropriate method.
The saved record includes the waveform, classification, and any symptom notes. A clinician can place it in context with your symptoms, medical history, examination, and—when necessary—a clinical ECG or other testing. The watch’s file is not a substitute for that evaluation.
Important limitations and safety precautions
The ECG app cannot detect every heart problem. Apple says it cannot detect a heart attack, stroke, blood clots, high blood pressure, congestive heart failure, high cholesterol, or other forms of arrhythmia. A sinus-rhythm result does not rule out disease, and an AFib result does not replace clinical evaluation.
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Call emergency services immediately for chest pain, pressure or tightness, shortness of breath, fainting, or other symptoms that could indicate a medical emergency. Do not wait for an ECG recording or rely on a reassuring watch result.
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How accurate is Apple Watch ECG?
Apple reports results from approximately 600 subjects: among classifiable results, it found 98.3% sensitivity for AFib classification and 99.6% specificity for sinus-rhythm classification. Apple cautions that these clinical-validation results reflect a controlled environment and that real-world use may produce more inconclusive or unclassifiable recordings.
These figures apply to the study conditions and classifiable results. They are not universal diagnostic accuracy for every user, heart rate, recording, or heart condition. A device can perform well at classifying the patterns it was designed to recognize while still missing other problems or producing an inconclusive result. See Apple’s ECG app guidance for its current explanation and limitations.
Which Apple Watch should you buy for ECG?
For ECG capability, choose an Apple Watch Series 4 or later or an Apple Watch Ultra; avoid the Apple Watch SE if ECG is a requirement. Then verify availability in your region and update software. App version matters because it changes the heart-rate range used for classification.
Do not choose a watch solely because of its ECG feature or assume that having the feature makes a purchase medically necessary. If you already have a compatible watch, setup and correct contact matter more than buying a newer model. Accessories such as a replacement band can help with everyday fit, while a charger can keep the watch ready, but neither changes what the ECG app can detect.
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ECG is separate from irregular-rhythm notifications
The ECG app and irregular-rhythm notifications are different Apple Watch features. An ECG is a deliberate, user-initiated 30-second recording. An irregular-rhythm notification is a separate background feature with its own availability, requirements, and limitations. Do not treat a sinus-rhythm ECG as proof that no later notification or rhythm change can occur, and do not treat an irregular-rhythm notification as the same thing as an ECG classification.
FAQ
Why can’t I find the ECG app on my Apple Watch?
First confirm that the watch is a Series 4 or later or an Apple Watch Ultra; Apple Watch SE does not support ECG. Then verify regional availability, update the iPhone and watch, and complete Health app onboarding at Browse > Heart > Electrocardiograms (ECG) > Set Up ECG App. If the app is missing after setup, install it from the iPhone Watch app under Heart.
Can Apple Watch ECG detect a heart attack?
No. Apple says the ECG app cannot detect a heart attack. It also cannot detect several other conditions, including stroke and heart failure. Seek emergency help for chest pain, shortness of breath, fainting, or other serious symptoms instead of waiting for a watch recording.
Why does my Apple Watch ECG say poor recording?
Movement, a loose fit, wet skin or watch, and electrical interference can contribute to a poor or unclassifiable recording. Clean and dry the contact surfaces, snug the band, rest your arm, touch the Digital Crown without pressing it, and repeat while resting.
Is Apple Watch ECG the same as a hospital ECG?
No. Apple Watch records a single-channel tracing similar to Lead I. A clinical ECG commonly uses 12 leads and is interpreted alongside symptoms, history, examination, and other tests.
The Bottom Line
For ECG, use a Series 4-or-later Apple Watch or any Ultra with current compatible software and regional support. Complete setup in Health, record while seated and still for 30 seconds, and treat the result as a limited rhythm snapshot—not proof that you are healthy or a replacement for medical care.
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