Handy Units: Unit Converter

Handy Units is a free, clean and easy unit converter. Open it and start typing: enter one number and every common unit appears in a single list, instantly — no switching back and forth between pairs.

FAST AND EASY
• Type a number and the whole list updates live; tap any row to make it the new starting point
• Pin the units you use, tuck the rest away, and keep the screen to what you need
• Copy a value, or the value with its unit, in one tap
• Convert right from Home Screen widgets — no need to open the app
• Works with Shortcuts, Siri and the Action button
• Built-in units work fully offline

CLEAN BY DESIGN
• Every feature is free — no sign-up, no subscription
• No pop-ups while you convert, just a calm, uncluttered screen
• Your settings and numbers stay on your phone
• 13 languages, plus unit presets for the US, UK, mainland China and more

EVERY CONVERSION SHOWS ITS FORMULA
Not just the answer — how it's worked out. Tap the formula to see:
• What the unit is, and how it relates to the base unit
• The formula to every other unit, such as °F = °C × 1.8 + 32
• Your own number worked through, step by step
• A short explanation where it helps, like why 0 °C isn't 0 °F

WRITE YOUR OWN FORMULAS
Need something that isn't built in? Make it:
• Add a unit to a category, like "my stride = 0.68 m"
• Build a whole conversion of your own: shoe sizes, fuel cost, salary to hourly pay…
• Pick how: a ratio, a few steps, or a formula with + − × ÷ ^ √ π and functions like round, log and if
• Try it as you type; the reverse conversion is worked out for you
• Build on exchange rates and the app's own conversions; keep changing numbers like fuel price as editable parameters
• Start from a ready-made template, or add a finished rule from the online library (needs internet)
• Share your conversions with friends and put them in widgets

COMPREHENSIVE
38 categories with more than 270 units, plus 60 currencies:
• Everyday: length, weight, temperature, area, volume, speed, fuel economy, EV efficiency, time, pressure, power, energy, data, blood glucose, currency
• Science and engineering: density, angle, force, torque, acceleration, flow rate, frequency, viscosity, illuminance, data rate, ratio and concentration
• Electricity and magnetism: voltage, current, resistance, capacitance, inductance, charge, magnetic field, magnetic induction, magnetic flux
• Radiation: radioactivity, absorbed dose, radiation dose
• Extension packs: ancient Chinese measures and biblical measures, with sources and modern equivalents

Exchange rates show the saved rates and when they were last updated, and refresh when you're online. Rates are for reference only, not bank transaction prices.

Tipping the developer is entirely optional and unlocks nothing — every feature stays free.