Dig into these tools. No other apps are needed.
Open Calculator and press on the calculator icon on the upper right of the screen. You’ll see a choice for the calculator: Basic, Scientific, or Math Notes and Convert. If you select Convert you will then have a number of additional choices: Angle, Area, Currency, Data, Energy and so on. Explore these to find what is useful to you. Choosing one like Currency lets you select among a various number of currencies and then which way to convert it.
Measure is a small app to let you measure the length of some item. Point your iPhone camera at a starting point and then click , then create points marking out the length or area you want to measure. You’ll see as you go that you can join points together, and measurements stay on screen until you tap the trash icon (top right). Use the list button (top left) to see the measurements you’ve made, and the photo capture button (lower right) to take a snap with the measurements overlaid on top. Practice with it to see how it woks.
At the bottom of the “Measure” screen you can select Level. With this application, you can see the angle something is from “level”. Try to measure different things and also you can tip the phone backwards or forwards to measure that dimension. It works in landscape or portrait mode. The display turns a green when your iPhone is perfectly level. You can also tap once on the screen to set a zero-degree level—which is helpful if you’re measuring a change in angle. Tap the screen again to revert back to standard operation.
Need a compass, open the Compass app in Utilities. Remove your phone from a case if the case has a magnet as this will interfere with compass operation. Turn around some to see your heading. Tap the screen to “lock” in a heading. If you are walking and get off course, you’ll see it turn red. Tap again to stop the “lock”. YOu’ll also see your current location in lat/long and the city (if applicable), as well as your elevation
To monitor sound levels, your iPhone will need to connect to your Apple Watch. “Open the Noise app on your watch, then tap Enable when prompted. You can then head to the Health app on iOS, tap the magnifying glass (bottom right), and choose Hearing > Environmental Sound Levels to see the readings. You can also monitor headphone volume in iOS from the Control Center: Swipe down from the top right of the screen, tap the + (plus) button in the top left corner, then Add a Control. Choose Headphone Levels under Hearing Accessibility, and you can then use this button at any time to check the volume levels coming into your ears.
From an article “5 clever iPhone tricks you might not know” David Nield, Popular Science, March 2026