The Calculator app can convert currencies, lengths, temperatures, and more without opening a separate app.

Here’s how:

1. Open the Calculator app
2. Tap the calculator icon in the top left (or top right on some layouts)
3. Select Convert
4. Choose the category (Currency, Length, Temperature, Speed, etc.)
5. Enter a number and pick the units or currencies you want

It updates with current exchange rates when online and works offline for most unit conversions.