Yes, the Calculator app on current iPhones converts units and currency, so for an occasional kilometers-to-miles or Celsius-to-Fahrenheit you don’t need to download anything. A dedicated converter app earns its place if you convert often, want to see a number in many units at once, cook from recipes in cups and grams, need US and UK measures kept apart, or share a household with Android phones.
How do you convert units in the iPhone Calculator? #
Apple documents the feature in its iPhone User Guide under Convert units or currency in Calculator. In recent iOS versions the steps look like this:
- Open Calculator.
- Tap the calculator button in the bottom-left corner, the same one that switches between Basic, Scientific and Math Notes.
- Turn on Convert.
- Tap the unit names above the number to choose a category and the two units you want.
- Type your number. The converted value appears alongside it.
Menus move around between iOS releases, so if your screen doesn’t match, Apple’s guide has the steps for the version you’re running. Currency conversion needs a connection to fetch rates.
What does the iPhone Calculator do well? #
- It’s already there. No download, no account, no ads.
- Math and conversion in one place. You can work something out in the calculator and convert the result without switching apps.
- Currency. Dedicated converters that compute everything offline, including ours, often skip currency. The Calculator includes it.
For a couple of conversions a week, that’s a strong case, and many people will never need more.
Where does a dedicated converter app do better? #
Seeing many units at once. The Calculator converts one pair at a time. A converter app that lists the whole category under the result answers the follow-up before you ask it. Type 26.2 miles and you see kilometers, meters, feet and nautical miles together, which helps when you’re not sure which unit the other person wants.
Cooking by ingredient. Converting “1 cup of flour” to grams needs to know it’s flour, because a cup of flour weighs about 120 g and a cup of honey about 336 g. Apple’s guide doesn’t describe any ingredient-based conversion, so for recipes you’ll want a kitchen converter or a chart like our cups to grams conversion chart.
US versus UK units. An imperial gallon is 20% bigger than a US gallon, and a UK pint is 568 mL where a US pint is 473 mL. A converter that lists both side by side stops you from picking the wrong one.
Cross-platform households. If some of your family use Android, an app available on both platforms means everyone gets the same answers in the same layout.
Speed for repeat conversions. Converter apps usually remember your last conversion or let you pin favorites, so the pair you use every day opens ready to go.
iPhone Calculator vs a converter app vs Google #
| iPhone Calculator | Convert Units Calculator | Google Search | |
|---|---|---|---|
| Cost | Free, built in | Free, one banner ad | Free, search ads |
| Currency | Yes, needs a connection | No, by design | Yes |
| Units shown per entry | One pair | Whole category | One pair |
| Cups to grams by ingredient | Not in Apple’s guide | Yes, 26 ingredients (v1.0.5) | Depends on the web result |
| US and UK gallons separate | Check your version | Yes (v1.0.5) | Choose from a list |
| Works offline | Test in airplane mode | Yes, all conversions | No |
| Android | No | Yes | Any browser |
The “check” entries are deliberate: Apple doesn’t publish a full unit list for Calculator, and it changes between iOS releases. Open Calculator, turn on Convert and look through the categories, or run the airplane-mode test in our offline unit converter article.
Worked example: the same question three ways #
Say you’re reading a British recipe that asks for 1 pint of milk and 250 g of flour, and your measuring jug is marked in US cups.
- iPhone Calculator: convert pints to cups for the milk, if the imperial pint is among its volume units. Then you still need a gram figure for a cup of flour from somewhere.
- Google: search each conversion separately, check that “pint” means an imperial pint, and trust whichever website the answer box quotes for flour.
- A converter app with UK units and a cooking category: UK pints to US cups in the Volume category (568 mL is 2.4 US cups), then 250 g of flour to cups in Cooking (2.08 cups, about 2 1/8).
None of this is hard. The app just saves steps when the question has more than one part.
Other converters already on your iPhone #
Safari and Google. Typing “5 km in miles” into Safari’s address bar searches Google (or your default engine), which shows a converter. It needs a connection. We look at the options beyond Google in Google unit converter alternatives.
Siri. You can ask conversion questions out loud, which is handy with flour on your hands.
When should you use which? #
- You convert a few times a month: stick with the Calculator.
- You need currency: the Calculator or another converter that downloads rates.
- You cook from mixed US, UK and metric recipes: a converter with a cooking category.
- You travel without data, or your family uses Android: a dedicated app that works offline on both platforms.
Convert Units Calculator is our app, built for the second half of that list. You type once and read every unit in the category, the answer updates as you type, and every conversion runs on the phone with no connection. Version 1.0.5 brings 19 categories and 140 units, with cups to grams for 26 ingredients and US and UK volumes side by side. It has no currency converter, so keep the Calculator for exchange rates. For a wider field of apps, see our best unit converter app comparison.
Frequently asked questions #
Can the iPhone Calculator convert units? #
Yes. Current versions of the Calculator app include a Convert option for units and currency. Apple’s iPhone User Guide describes it under “Convert units or currency in Calculator.”
Does the iPhone Calculator convert currency? #
Yes. It needs an internet connection to fetch exchange rates, so the rates you see offline may be out of date.
Can the iPhone Calculator convert cups to grams? #
Apple’s guide doesn’t describe ingredient-based conversion, and cups to grams can’t be done correctly without knowing the ingredient. Use a kitchen converter or a chart that lists grams per cup for each ingredient.
Is a separate unit converter app worth it? #
It’s worth it if you convert often, need to see several units at once, cook from recipes in different systems, or want the same app on iPhone and Android. For occasional conversions, the built-in Calculator is enough.
Does the iPhone Calculator’s converter work without internet? #
Currency rates need a connection. For other units, test it: turn on airplane mode, reopen Calculator and try a conversion on your iOS version before you rely on it abroad.