The Measure app uses augmented reality (AR) technology to turn your iOS device into a tape measure. You can quickly gauge the size of objects, automatically detect the dimensions of rectangular objects, and save a photo of the measurement for later.
Before you start
First, make sure that you're using iOS 12 on iPhone SE, iPhone 6s or later, iPad (5th Generation or later), or iPad Pro. Also make sure that you're in a place with good lighting.
How to take a single measurement
- Open the Measure app, then follow the onscreen instructions that ask you to move your iPhone or iPad 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
. - Slowly move your device until the dot is over the ending point of your measurement, then tap 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 
, 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 iPhone or iPad to place the dot over another location on or near the object.
- Tap to start the second measurement, then move your device to place the dot somewere along the existing measurement.*
- Tap again and the second measurement appears.
- Repeat these steps to take as many measurements as you'd like.
Tap 
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 iPhone or iPad detects that the object you're measuring is a square or rectangle, it automatically places a measurement box around the object. Tap 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 level
The Measure app also has a level that you can use to straighten a vertical object, such as a picture frame, or level a flat surface, such as a table.
How to straighten a vertical object
- Tap Level in the Measure app.
- Place one of the edges of your iPhone or iPad on the object that you want to straighten. The level shows you the number of degrees off center the object is. Adjust the object until the app shows 0 degrees and turns green.
How to level a flat surface
- Tap Level in the Measure app.
- Place your device flat on the surface. The app uses two circles and degrees to show you how far off-center the surface is. When the surface is level, a single circle shows 0 degrees and the level turns green.
You can also calibrate the level to use a starting point of your choice. Hold your device at the position that you want, then tap the screen to set the level at 0 degrees. Any subsequent movement of your device shows how many degrees it's off from the level starting point that you set.