Unit Converters
Measurements follow you everywhere. A furniture seller quotes inches while your tape measure reads centimetres; a recipe needs grams but your kitchen scale shows ounces; a weather report gives Fahrenheit and you think in Celsius. Getting the units wrong is not a small mistake — it can double a quantity or halve it, and that ruins recipes, fittings and journeys alike. This page gathers the unit converters on all-calculators.info so you can switch between metric and imperial in seconds, with the formula and a worked example under every tool. Students, builders, cooks, travellers and shopkeepers all land here for the same reason: one quick conversion beats a whole page of arithmetic. Every converter is free, works on your phone or computer, and needs no sign-up.
Popular Calculators
- Angle Converter — convert degrees, radians and gradians.
- Area Converter — convert square metres, square feet, acres and hectares.
- Cooking Converter — convert cups, tablespoons, millilitres and grams for recipes.
- Data Storage Converter — convert megabytes, gigabytes and terabytes.
- Energy Converter — convert joules, calories and kilowatt-hours.
- Fuel Consumption Converter — convert litres per 100 km and miles per gallon.
- Length Converter — metres, feet, inches, km and miles.
- Power Converter — convert watts, kilowatts and horsepower.
- Pressure Converter — convert pascals, bar and psi.
- Roman Numeral Converter — convert numbers to Roman numerals and back.
- Shoe Size Converter — convert shoe sizes between UK, US and EU.
- Speed Converter — convert km/h, mph and metres per second.
- Temperature Converter — Celsius, Fahrenheit and Kelvin.
- Time Converter — convert seconds, minutes, hours and days.
- Volume Converter — convert litres, gallons and millilitres.
- Weight Converter — kg, pounds, ounces and stones.
How to Choose the Right Calculator
Length Converter
The Length Converter switches between metres, feet, inches, kilometres and miles — the five units you meet most in daily life. Use it when buying furniture, reading a plot size, planning a trip distance or converting a height. It handles linear measures only: for areas, such as the floor of a room, use the Square Footage Calculator instead, and for material quantities pick the Weight Converter when you need mass rather than length.
Weight Converter
The Weight Converter moves between kg, pounds, ounces and stones — the kitchen, market and luggage units. Use it for recipes, parcel weights, gym numbers and grocery shopping. Weight and length are different physical quantities, so this tool cannot turn metres into kilograms: pick the Length Converter for distances and the Weight Converter for anything you would weigh on a scale.
Temperature Converter
The Temperature Converter translates between Celsius, Fahrenheit and Kelvin, which matters because the three scales start at different points and grow at different rates. Use it for weather, cooking and science homework. Unlike the other converters here, temperature is not a straight multiplication — 20 degrees Celsius is not double 10 degrees — which is exactly why a tool beats mental maths.
Good to Know
Four conversion habits worth keeping:
- Check the direction: converting 5 km to miles gives a smaller number, so if your answer grew, you converted the wrong way round.
- Mind the decimal places: two decimals are plenty for cooking and shopping; keep more when the result feeds another calculation.
- Never mix units in one calculation: turn everything into the same unit first — 1 metre plus 30 centimetres is 1.3 metres, not 31 of anything.
- Remember temperature is special: 0 degrees Celsius is 32 degrees Fahrenheit, so always convert before comparing weather reports from two countries, and never add Celsius and Fahrenheit figures together.
Frequently Asked Questions
How many kilometres is a mile?
One mile is about 1.609 kilometres, so 10 miles is roughly 16.1 km. For shorter distances the factor works just as well: 5 miles is about 8.05 km. The Length Converter uses the full factor, so use it when precision matters.
How many pounds is a kilogram?
One kilogram is about 2.2 pounds, so 10 kg is roughly 22 pounds — and it works the other way too, with 10 pounds being about 4.5 kg. The Weight Converter gives the exact figure when you need it.
Why can’t I convert Celsius to metres?
Because they measure different things: temperature is not a length. Temperature, length and weight are separate dimensions, and each converter here only converts within its own — converting across quantities has no meaning.
Are these converters free?
Yes. Every converter on this page is free, with no sign-up, and works on your phone or computer — bookmark this page for the next time you need a quick conversion.
Why use these calculators?
Every calculator on this page is free, works on your phone or computer, and shows the formula and a worked example under the tool — so you can see exactly how your answer was calculated, not just the answer.