All 12 categories
Every conversion from the iPhone works the same way on your wrist.
A closer look
Looks right in light and dark mode. Tap any screenshot to enlarge.
On your wrist
A native Apple Watch app with every category from your iPhone — including live currency, synced favorites, and one-tap complications.
Live currency, synced
Exchange rates push automatically from your iPhone. The Watch never has to fetch them itself.
Favorites in sync
Star a category on the phone — it appears at the top on the Watch, instantly.
Haptic feedback
Every action confirms with a subtle tap. Useful when you can't look down.
Requires watchOS 10.6 or later
On your Home Screen
Five widgets across three sizes — launchers for fast access and live currency rates that refresh automatically.
Twelve categories
Everything you need, nothing you don't.
Currency
162+ currencies with live exchange rates. Works offline with cached rates.
Cooking
Ingredient-specific conversions. Cups of flour to grams with accurate density.
Distance
Meters, feet, miles, kilometers, and more. Metric and imperial.
Weight
Grams, pounds, ounces, kilograms, stone, and metric tons.
Volume
Liters, gallons, pints, fluid ounces, and milliliters.
Area
Square meters, acres, hectares, square feet, and more.
Temperature
Celsius, Fahrenheit, and Kelvin conversions.
Pressure
PSI, bar, atmospheres, pascals, and millibars.
Speed
mph, km/h, knots, meters per second, and more.
Power
Watts, kilowatts, horsepower, and BTU per hour.
Data
Bytes, kilobytes, megabytes, gigabytes, and terabytes.
Fuel
Miles per gallon, liters per 100 km, and km per liter.
Why Flip Unit
Every detail considered. Especially the small ones.
Privacy Protected
No ads, no tracking, no data collection. All conversions stay on your device. No account required.
Accessibility-First
Full VoiceOver support, Dynamic Type, haptic feedback, and high contrast. Built for everyone from day one.
Smart Conversions
Ingredient-specific cooking conversions with density calculations. Cross-category conversions that just work.
Fast & Efficient
Real-time conversions as you type. Conversion history, favorite categories, and smart search.
Light or Dark Mode
Follows your system theme by default, or pick one. The app, the Watch, and every widget all match.
Always Fresh
Currency rates refresh automatically in the background. Widgets and the Watch stay current without ever opening the app.
Finally, a converter that speaks your language
Built for blind and low-vision users from the very first line of code.
- Full VoiceOver support with clear announcements
- Dynamic Type from small to accessibility sizes
- Multi-sensory feedback: visual, haptic, and audio
- Minimum 44pt touch targets exceeding guidelines
- Reduce Motion support for sensitive users
Frequently Asked Questions
Quick answers to common questions.
How do I convert units?
Select a category from the home screen, enter a number, choose your "From" and "To" units using the dropdowns, and see your result instantly at the top of the screen.
How do currency conversions work?
Currency rates refresh every six hours when you have an internet connection — the app, your widgets, and the Apple Watch all get updated automatically. The app detects your locale to set default currencies. Once rates are downloaded, they're cached so you can convert currencies offline using the last known values.
Does Flip Unit work on Apple Watch?
Yes. There's a native Apple Watch app with all 12 categories, plus 12 circular complications you can add to any watch face for one-tap access. Currency rates sync automatically from your iPhone, so the Watch never has to fetch them on its own.
What widgets are available?
Five widgets across three sizes: a single-category launcher, a four-pack launcher, a six-pack launcher, plus a live currency widget. They work on both the Home Screen and the Lock Screen, and each one is independently configurable.
Do I need to open the app for widget rates to update?
No. Currency rates refresh automatically in the background, so widgets stay current without you ever opening the app. The Apple Watch gets fresh rates pushed from your iPhone the same way.
Why does my cooking conversion say "(approx)"?
Cross-category conversions between volumes (cups, tablespoons) and weights (grams, ounces) use density estimates because different ingredients have different weights. For the most accurate results, use ingredient-specific cups like "Cup of Flour" or "Cup of Sugar" which have precise density values.
How do I clear my conversion history?
Go to Settings > History Limit and select a lower number to automatically trim older entries. To clear all app data, go to iOS Settings > Flip Unit > Clear Data, or simply uninstall and reinstall the app.
How do I change the app theme?
Open the Settings tab and tap Theme. Choose from System (follows your device setting), Light, or Dark mode.
How do I add categories to favorites?
On the home screen, swipe left on any category card to reveal the favorite option. Tap the star icon to add it to your Favorites section at the top of the home screen.
Does the app work offline?
Yes. All 12 categories work completely offline — Distance, Weight, Volume, Area, Temperature, Pressure, Speed, Power, Data, Fuel, Cooking, and Currency. Currency uses cached exchange rates from the last online update; everything else works without any network at all.
How many currencies are supported?
Flip Unit supports 162+ world currencies with exchange rates provided by ExchangeRate-API. Rates refresh every six hours when you're connected to the internet.
What iOS and watchOS versions do I need?
iOS 17.0 or later for the iPhone app, iOS 18.0 or later for widgets, and watchOS 10.6 or later for the Apple Watch app.
Is the app accessible?
Absolutely! Flip Unit is built accessibility-first with full VoiceOver support, Dynamic Type scaling, haptic feedback, Reduce Motion support, and high contrast colors.
Why are some results in scientific notation?
Very large numbers (over 1 million) or very small numbers (under 0.001) are displayed in scientific notation for better readability. For example, 1,500,000 may display as 1.5e6.
Does Flip Unit collect my data?
No. Flip Unit collects absolutely no personal data. All conversions happen locally on your device. See our Privacy Policy for full details.
Is there an Android version?
Flip Unit is currently available only for iOS (iPhone). There are no plans for an Android version at this time.