It’s surprising how often we need to measure things. Whether it’s tracking the kids’ heights or working out if thing X will fit in space Y, the ability to measure things with our phones is really useful.
Both iOS and Android enable you to point your phone at things to see how big, small, long or far away they are, and they can also do useful things such as help you calculate the area of an object or dimension. In most cases the apps use augmented reality to map what your camera sensor sees, overlaying measurements and lines on whatever you point your phone camera at.
Before we start it’s important to stress the limits of smartphone measuring apps. No matter how good the phone or how clever the app, it won’t deliver 100% accuracy: we’ve found with the iPhone 12 Pro and its built-in LiDAR scanner that the accuracy is just over 95% in most cases.
Like most (but not all) measuring apps, Apple’s Measure is not designed for precision measurements: while we’ve found it to be pretty accurate for measuring physical objects and the odd child, it’s not as accurate as the laser measures or good old-fashioned tape measures that professional tradespeople use.
If you need accurate measuring for your job or project, a laser measure with Bluetooth connectivity is a better option. For everything else, read on.
Since iOS 12, your iPhone has included an app called Measure that you can use to accurately determine dimensions. You can use it to see how long something is, and you can also use it to calculate the square footage/square metres of objects. In a nice touch you can see how tall someone is simply by getting their whole body in the viewfinder.
Your accuracy will depend on what version of iPhone you have. The iPhone 12 Pro and iPhone 12 Pro Max have a LiDAR scanner that makes the Measure app more accurate on those devices. We’re also expecting this feature to be available on the iPhone 13, too.
When you launch the Measure app it’ll look a lot like the Camera app: that’s because it uses your phone camera to do its measuring. When you point the camera at an object you’ll see this white dot appear.
You don’t need to keep the whole object or person in frame to measure it. Get as close as you need and when you’ve got the dot in the right place, tap the + icon to set the start point.
Measure has some auto-detection that tries to help, which is what the faint yellow lines you can see in the screenshot are. Don’t worry too much about getting the start point in the precise position: you can adjust it later.