For better or worse, smartphones have become a Swiss Army knife for many of us. In my own life, I rely on it for everything from counting calories to putting on a soundtrack while I ride my EUC. Even my wife and son depend on my phone, aside from being able to get in touch with me -- it's how I manage Family Sharing for Apple devices, and adjust the smart home automations we use every day.
In this guide I'm going to cover the basic requirements, as well as a few sample scenarios illustrating what commands you need to use. Don't worry -- the most complicated thing is knowing the math involved in the first place.
What do you need to do math and conversion in Messages?
A few simple steps, and some notes
On a technical level, the only thing you need to do is update your iPhone to iOS 18 or later. In fact as of this writing, I'd strongly recommend updating to at least iOS 26, which is compatible with every device from the iPhone 11 and second-generation iPhone SE onward. It's unlikely to add new math or conversion options, but Apple is constantly tightening security, and there's no sense leaving other feature enhancements by the wayside. I've tested iOS 26 long enough to know there aren't any major downsides.
To update iOS, follow these steps:
- Make sure your iPhone is connected to Wi-Fi, and reasonably well-charged -- I'd say at least 50%. It should also be backed up, whether to iCloud or your computer, in case the worst happens.
- Go to Settings > General > Software Update.
- If an update is available, tap on the appropriate button to begin the install process. Note that if a major upgrade is available -- like the leap from iOS 18 to 26 -- it may be listed as a second option near the bottom.
- Sit back and be patient. Your phone will need to download the software, apply it, then reboot. The whole process could take upwards of 15 to 30 minutes or longer, depending on your internet bandwidth and the speed of your phone's processor.
As a side note, you can also take advantage of these features on your iPad, so it's worth updating iPadOS as well. The steps are identical to iOS for everything mentioned in this article. The only catch is that Apple doesn't foreground Messages on iPads, so you'll need to search for the app and/or add it to your dock or homescreen.
How to do math in Messages
Basic math and splitting tips
For most equations, it's often best to use Calculator instead. In Messages, you don't have to hit Send and share the results with anyone if you don't want to -- but the default iOS keyboard forces you to toggle between multiple layouts to reach math symbols, and that can be frustrating if all you're trying to do is add or subtract a couple of numbers.
To get started, begin a Messages conversation with someone, or open an existing chat. This should, of course, be a specific person or group if you are planning to share.
You can build an equation with or without spaces between numbers and symbols. All equations need to end in an equal (=) symbol, however -- once you add this, Messages will run the calculation, and display the results in a lighter shade. Tap the equation if you actually want to insert it into chat.
Use + and - for addition and subtraction, respectively. For multiplication, both x and * will work. Division is done with /, since there's no included division symbol.
Splitting a bill with a tip (equally) is just a question of knowing what the formula looks like. Start with the base bill, then multiply it by 1.xx, where xx is the tip percentage. That equation is put in parentheses to isolate it. Then you add / y, where y is the number of people splitting. A typical calculation might look like ($100 x 1.20) / 4 = $30. This will naturally get more complex if you're looking to split just the tip, or do things unevenly. For that you should be talking to Siri or using a purpose-built tip calculator app.
Advanced math
Messages may not be the best place to do your trigonometry homework either, but you can write out some equations in Messages instead of having to switch to Calculator's Scientific mode. I won't delve into the specifics here -- my own trigonometry skills aren't just rusty, they're sitting on my front lawn -- but if you want to figure out something like the sine, cosine, or tangent, all you need to do is use the appropriate abbreviation paired with parentheses, e.g. sin(100) or tan(50).
It seems safe to say that you won't be doing algebra or calculus in Messages, and there's no easy way of representing exponents.
I'm not sure how far this goes, so it's worth experimenting. It seems safe to say that you won't be doing algebra or calculus in Messages, and there's no easy way of representing exponents, much less advanced physics terms.
The best place for doing high-level math on an iPhone or iPad may be the Calculator app's Math Notes tool. In fact, with an iPad and a stylus, there's not much restriction on what you can do -- you can even draw graphs. Be sure your work is as legible as possible.
How to do unit conversions in Messages
Natural language to the rescue
Thankfully, unit conversion is not only simple, it's simpler than you might expect for some of the most common requests. It's a matter of knowing abbreviations, and which conversions are defaults. If you're at the gym, for instance, an expression like "205kg=" will automatically convert from kilograms into pounds. "37c=" will get you from Celsius to Fahrenheit. Results and the characters needed may depend on the region you're based in.
One thing that doesn't seem to work is currency conversion.
For less obvious conversions, you'll have to type out something closer to a real sentence, e.g. "55 in to ft =" if you want to shift from inches to feet. There's no Apple manual explaining your options -- all you can do is test things out and end everything with =.
One thing that doesn't seem to work is currency conversion. That's not surprising, perhaps, since Messages would have to fetch real-time exchange data. For that, you'll want to talk to Siri or use Google Search, if not visit a reputable financial website. You don't want to find out the hard way that you're getting outdated information.