In iOS 15, unit and currency conversions are handled by Spotlight, but in iOS 16 you can perform these and many other unit conversions anywhere in the operating system that you can select text. Keep reading to learn how it works.

ios 16 lock screen feature
Apple hasn't publicized this handy feature, but iOS 16 is capable of performing a range of unit conversions that appear in inline text on the fly. The built-in ability is on call across a range of stock apps like Messages, Mail, Calendar, Notes, Reminders, and more, and is available at a touch of the screen.

For example, say you're in the U.S. and you're chatting via Messages with someone in the United Kingdom, and they mention the temperature where they are in degrees Celsius.

messages
There's no need to exit the app or even ask Siri to convert it to Fahrenheit for you – simply long press the underlined temperature in the chat bubble, and you'll see a pop-over that gives you the conversion (along with Kelvin, in case you were wondering) along with the option to copy it to the clipboard.

Here's another example. Let's say you receive an email in the Mail app from someone based in the U.S. country, informing you of a product event announcement that is due to take place at 10:00 a.m. PT. All you have to do is long press on the underlined time and iOS will provide you with the equivalent time in the time zone that your iPhone is set to, along with the option to add a Calendar event.

mail
In fact, iOS 16 can work its conversion magic on a range of units including the following:

  • Currency
  • Distance
  • Temperature
  • Time Zones
  • Volume
  • Weight

So whenever you see underlined units in Apple's latest mobile OS, remember that a long press will very likely give you the conversion that makes most sense to you. (Credit goes to MacStories editor in chief Federico Viticci for spotting the feature.)

Popular Stories

iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro Launching in Three Months With These 12 New Features

Saturday June 14, 2025 5:45 pm PDT by
The iPhone 17 Pro and iPhone 17 Pro Max are three months away, and there are plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models as of June 2025:Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone X through iPhone 14 Pro have a...
iPadOS 26 App Windowing

Apple Explains Why iPads Don't Just Run macOS

Friday June 13, 2025 7:46 am PDT by
iPadOS 26 allows iPads to function much more like Macs, with a new app windowing system, a swipe-down menu bar at the top of the screen, and more. However, Apple has stopped short of allowing iPads to run macOS, and it has now explained why. In an interview this week with Swiss tech journalist Rafael Zeier, Apple's software engineering chief Craig Federighi said that iPadOS 26's new Mac-like ...
Logitech Logo Feature

Logitech Announces Two New Accessories for WWDC

Friday June 13, 2025 7:22 am PDT by
Alongside WWDC this week, Logitech announced notable new accessories for the iPad and Apple Vision Pro. The Logitech Muse is a spatially-tracked stylus developed for use with the Apple Vision Pro. Introduced during the WWDC 2025 keynote address, Muse is intended to support the next generation of spatial computing workflows enabled by visionOS 26. The device incorporates six degrees of...
iphone 16 pro models 1

17 Reasons to Wait for the iPhone 17

Thursday June 12, 2025 8:58 am PDT by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models simultaneously, which is why we often get rumored features months ahead of launch. The iPhone 17 series is no different, and we already have a good idea of what to expect from Apple's 2025 smartphone lineup. If you skipped the iPhone...
iOS 26 Feature

Apple Seeds Revised iOS 26 Developer Beta to Fix Battery Issue

Friday June 13, 2025 10:15 am PDT by
Apple today provided developers with a revised version of the first iOS 26 beta for testing purposes. The update is only available for the iPhone 15 and iPhone 16 models, so if you're running iOS 26 on an iPhone 14 or earlier, you won't see the revised beta. Registered developers can download the new beta software through the Settings app on each device. The revised beta addresses an...
Mac Studio Feature

Apple Begins Selling Refurbished Mac Studio With M4 Max and M3 Ultra Chips at a Discount

Thursday June 12, 2025 10:14 am PDT by
Apple today added Mac Studio models with M4 Max and M3 Ultra chips to its online certified refurbished store in the United States, Canada, Japan, Singapore, and many European countries, for the first time since they were released in March. As usual for refurbished Macs, prices are discounted by approximately 15% compared to the equivalent new models on Apple's online store. Note that Apple's ...
m4 macbook air pink

Apple Now Selling Refurbished M4 MacBook Air Models

Friday June 13, 2025 3:34 pm PDT by
Apple today added M4 MacBook Air models to its refurbished store in the United States, making the latest MacBook Air devices available at a discounted price for the first time since they launched earlier this year. Both 13-inch and 15-inch MacBook Air models are available, with Apple offering multiple capacities and configurations. The refurbished devices are discounted by approximately 15...