Cancels: Unit Calculator
A tape that checks dimensions
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
Type 3.4 kW × 6 h × 0.24 £/kWh and get £4.90, with the units struck through as they cancel. Try 3 m + 4 s and it refuses, instead of quietly guessing wrong.
A calculator that understands what it's calculating.
Type 3.4 kW × 6 h × 0.24 £/kWh and Cancels gives you £4.90 — because it knows a kilowatt times an hour times a price-per-kilowatt-hour is a price, and it shows you the kW and the h cancelling out to get there. Type 3 m + 4 s and it refuses, with "Can't add length to time," instead of quietly returning a wrong number.
Under the hood, every unit is built from seven physical dimensions plus currency, so compound units aren't a lookup table — they're algebra. £/kWh, kg·m/s², mi/gal, GB/Mbps: all of it composes from the same handful of rules, which is also why a genuine mismatch is caught instead of coerced.
WHAT IT DOES
• A running tape, not a single-answer calculator — every line stays, and you can reference an earlier result with @2 and keep going.
• Tap a line to see the reduction: which units cancelled against which, step by step, ending in the result.
• Mixed and compound units throughout — feet and inches together, kilowatt-hours, miles per gallon, gigabytes per second — typed or built from the on-screen palette.
• Edit any line and everything below it recalculates, instantly.
• A real refusal, in plain English, when units don't match — no silent wrong answers, and currency is never converted because there's no exchange rate on your device to convert with.
• A searchable reference of every supported unit, grouped by what it measures.
• Multiple tapes, so today's grocery math and this month's energy bill don't have to share a screen.
• Dark mode, Dynamic Type and VoiceOver support throughout.
WHO IT'S FOR
Anyone who's ever converted a recipe, sized a room, priced out electricity use, or double-checked a physics problem by hand — and wanted the calculator to catch the mistake before they built on top of it.
PRIVACY
Cancels works entirely on your device. There's no account, no network connection, and nothing is ever sent anywhere. Everything you type stays on this device, permanently, unless you delete it yourself.
Ratings & Reviews
- This app has not received enough ratings or reviews to display an overview.
The developer, Jarle Hansen, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Provider
- Jarle Hansen
- Size
- 1.1 MB
- Category
- Utilities
- Compatibility
Requires iOS 26.0 or later.
- iPhone
Requires iOS 26.0 or later. - Mac
Requires macOS 26.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 26.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © Jarle Hansen