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The Measure app uses augmented reality (AR) technology to turn your device into a tape measure. You can gauge the size of objects, automatically detect the dimensions of rectangular objects, and save a photo of the measurement. And with iPad Pro 12.9-inch (4th generation), iPad Pro 11-inch (2nd generation), iPhone 12 Pro, and iPhone 12 Pro Max, you can measure objects more easily with visible guides, measure a person’s height, and see a history of your measurements.
Before you start
First, make sure that your device's software is up to date. The Measure app works on these devices:
Also make sure that you're in a place with good lighting.
How to take a single measurement
- Open the Measure app, then follow any onscreen instructions that ask you to move your device around. This gives your device a frame of reference for the object you're measuring and the surface it's on. Keep moving your device until a circle with a dot in the center appears.
- Move your device so that the dot is over the starting point of your measurement, then tap the Add button .
- Slowly move your device until the dot is over the ending point of your measurement, then tap the Add button again.
After you take a measurement, you can adjust its starting and ending points. Touch and hold one of the points, then drag it where you want it to go. The measurement changes as you move the point.
Save your measurement
While the measurement is displayed, you can tap the number to see it in inches and centimeters. Tap Copy, and the value is sent to your clipboard so you can paste it into another app. Tap Clear to start over.
You can also take a photo that shows the object and its measurement. Just tap the Shutter button , and the photo appears in the lower-left corner of your screen. Tap it to make edits using Markup, or swipe left to save it to your Photos app.
How to take multiple measurements
- After you take the first measurement, move your device to place the dot over another location on or near the object.
- Tap the Add button to start the second measurement, then move your device to place the dot somewhere along the existing measurement.*
- Tap the Add button again and the second measurement appears.
- Repeat these steps to take as many measurements as you'd like.
Tap the Undo button to remove the most recent measurement, or tap Clear to start over.
* Additional measurements must start or end somewhere along an existing measurement. Otherwise, all previous measurements are replaced by the newest one.
Measure a rectangle
If your device detects that the object you're measuring is a square or rectangle, it automatically places a measurement box around the object. Tap the Add button and measurements appear for the object's width and length. Move your device slightly, and the object's calculated area appears.
While the measurement is displayed, you can tap the calculated area number to see the length of the diagonal as well as the area in square inches or square meters.
Use the Measure app with iPad Pro 12.9-inch (4th generation), iPad Pro 11-inch (2nd generation), iPhone 12 Pro, and iPhone 12 Pro Max
iPad Pro 12.9-inch (4th generation), iPad Pro 11-inch (2nd generation), iPhone 12 Pro, and iPhone 12 Pro Max use the LiDAR Scanner to help you measure objects more quickly and accurately with the Measure app.
Not sure if your device has a LiDAR Scanner? Find out which iPad model you have or which iPhone model you have.
Measure a person's height
When the Measure app detects a person in the viewfinder, it automatically measures their height from the ground to the top of their head, hat, or hair. You can tap the shutter button to take a photo of the person with their height measurement. Then you can use Markup on the photo, save it, and share it.
Use vertical and edge guides
On iPad Pro 12.9-inch (4th generation), iPad Pro 11-inch (2nd generation), iPhone 12 Pro, and iPhone 12 Pro Max, guide lines help you measure the height and straight edges of furniture, countertops, and other objects easily and precisely. Guide lines appear automatically along edges and when making a vertical measurement.
Snap your starting and ending points to the yellow guide line, then tap a measurement to see the expanded information that iPad Pro provides. You can view the measurement's elevation, distance away, angle, and more.
See more granular measurements with Ruler View
The Measure app on iPad Pro 12.9-inch (4th generation), iPad Pro 11-inch (2nd generation), iPhone 12 Pro, and iPhone 12 Pro Max adds a ruler overlay to line measurements, showing you the object's dimension in granular increments. Move your iPad Pro close to a line measurement to see the ruler view appear, then tap the shutter button to take a photo so you can use the increments for planning projects.
See your measurement history
Tap the list button to view all the measurements that you've taken during the current session, including screenshots that you took. This helps you keep track of dimensions as you measure a space or series of objects. You can copy the dimensions into Notes, Mail, or any app you want to save your list in, or clear them to start over.
Learn more
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You can also use your iPhone or iPod touch as a level.
How to check your heart rate
You can check your heart rate any time using the Heart Rate app. Open the app, then wait for Apple Watch to measure your heart rate. You can also view your resting, walking, breathe, workout, and recovery rates throughout the day. To easily open the app, add the Heart Rate complication to your watch face or add the Heart Rate app to the Dock.
You can also turn on heart rate notifications, so you know if your heart rate remains above or below a chosen beats per minute (BPM), or to occasionally check for an irregular heart rhythm.
Heart rate notifications and resting and walking rates are available only on Apple Watch Series 1 or later. Irregular rhythm notifications are available only with watchOS 5.1.2 or later. To enable irregular rhythm notifications, the notifications must be available in your country or region and you must be in the country or region where you purchased your device. Learn where irregular rhythm notifications are available.
When Apple Watch measures your heart rate
When you use the Workout app, Apple Watch measures your heart rate continuously during the workout and for 3 minutes after the workout ends to determine a workout recovery rate. If you don't see your heart rate, check your settings.
This information, as well as other data it collects, helps Apple Watch estimate how many calories you’ve burned. In addition, Apple Watch measures your heart rate throughout the day when you’re still, and periodically when you’re walking (Apple Watch Series 1 or later). Since Apple Watch takes these background readings based on your activity, the time between these measurements will vary. Apple Watch also calculates a daily resting rate and walking average by correlating background heart rate readings with accelerometer data when sufficient background readings are available. You can control which third-party apps have access to your health data from the Health app in Sources.
Some anomalies may appear in the displayed data, resulting in occasional heart rate measurements that are abnormally high or low.
How Apple Watch measures your heart rate
The optical heart sensor in Apple Watch uses what is known as photoplethysmography. This technology, while difficult to pronounce, is based on a very simple fact: Blood is red because it reflects red light and absorbs green light. Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. When your heart beats, the blood flow in your wrist — and the green light absorption — is greater. Between beats, it’s less. By flashing its LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute — your heart rate. The optical heart sensor supports a range of 30–210 beats per minute. In addition, the optical heart sensor is designed to compensate for low signal levels by increasing both LED brightness and sampling rate.
The optical heart sensor can also use infrared light. This mode is what Apple Watch uses when it measures your heart rate in the background, and for heart rate notifications. Apple Watch uses green LED lights to measure your heart rate during workouts and Breathe sessions, and to calculate walking average and Heart Rate Variability (HRV).
Apple Watch Series 4, Series 5, or Series 6* also have built-in electrodes in the Digital Crown and the back of Apple Watch, which can measure the electrical signals across your heart when used with the Heart Rate app or the ECG app. When you place your finger on the Digital Crown, it creates a closed circuit between your heart and both arms, capturing the electrical impulses across your chest.
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To use the electrical heart sensor to measure your heart rate, open the Heart Rate app and place your finger on the Digital Crown. You will get a faster reading with higher fidelity — getting a measurement every second instead of every 5 seconds. You’ll see 'ECG' in Heart Rate Context when looking at recorded data for Heart Rate in the Health app. You can also use the electrical heart sensor to take an ECG with the ECG app.
*ECG isn't supported on Apple Watch SE. The ECG app is currently available only in certain countries and regions. Learn where the ECG app is available.
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For best results
Start with a good fit. Even under ideal conditions, Apple Watch may not be able to get a reliable heart rate reading every time for everybody. And for a small percentage of users, various factors may make it impossible to get any heart rate reading at all. But there are things you can do to help Apple Watch get the most consistent and best heart rate readings possible. Learn what else affects your reading.