Unit Flip: free unit conversion game, °C to °F, km to miles

What is Unit Flip?

20 °C in °F? 10 km in miles? 5 kg in pounds? Pick the closest of four answers for 60 seconds, using quick tricks like “double and add 30” or “× 1.6”. Level 2 flips the direction, level 3 adds inches, centimetres, feet and metres.

Unit Flip is a free quick game about the conversions people look up every day: Celsius to Fahrenheit, kilometres to miles, kilograms to pounds, and back. Each question shows four answers; pick the closest before the clock runs out.

You don't need a calculator. Only one answer is close to the real value, so a quick trick gets you there: double and add 30 for °C to °F, × 1.6 for miles to km, double plus a tenth for kg to pounds. Every answer shows the exact rule and the trick. Level 2 flips the direction, and level 3 adds centimetres, inches, metres and feet.

At a glance

Category

Quick Games

Difficulty

Medium

Play time

1 min

Price

Free, in your browser, sign-up optional

How to play

Read the conversion

A value to convert appears, like “20 °C in °F?”.

Pick the closest

Tap the closest of four answers, or press 1 to 4. Only one is close; the others are clearly off.

Time

You have 60 seconds. Level 2 starts after 5 right answers, level 3 after 12. A wrong answer costs 2 seconds and resets your streak.

Score

Each right answer scores 10, 15 or 20 points by level plus up to 5 for speed, multiplied by your streak: ×2 after 4 right in a row, ×3 after 8, ×4 after 12.

Scoring

Each right answer scores 10 points at level 1, 15 at level 2 and 20 at level 3, plus up to 5 for answering within 4 seconds, multiplied by your streak: ×2 after 4 right in a row, ×3 after 8, ×4 after 12. Level 2 (both directions) starts after 5 right answers, level 3 (adds inches, centimetres, feet and metres) after 12.

The run lasts 60 seconds. A wrong answer costs 2 seconds, resets your streak and shows the exact rule and a quick trick. Your best score is kept in this browser.

What it trains

Estimation

Getting close fast with tricks like double and add 30, or × 1.6.

Number sense

Spotting the answer that is about the right size.

Everyday conversions

Temperatures, distances, weights and lengths between metric and imperial.

Strategy and tips

°C to °F

Double it and add 30. Exact: × 1.8 + 32. Great for weather.

°F to °C

Take off 30 and halve. Exact: take off 32, then ÷ 1.8.

Miles and km

Miles × 1.6 = km; km × 0.6 = miles. A 10 km run is about 6.2 miles.

Kilos and pounds

kg × 2.2 = lb: double it, then add a tenth of that. Halve pounds and take off a tenth to get kg.

Inches and feet

1 inch = 2.54 cm; 1 metre is about 3.3 feet.

Why play Unit Flip?

Recipes, weather apps, running plans and travel all mix units. Knowing a quick trick for each turns a search into a two-second sum in your head, and the habit of estimating first catches mistakes.

Frequently asked questions