Free Online Unit Converter
Convert length, weight, temperature, area, volume, speed, time, data, pressure, energy and more in one fast and accurate tool. No sign-up needed.
What is a unit converter?
A unit converter changes a measurement from one unit to another without changing its real value. For example, 1 mile equals 1.609344 kilometres, and 100 °C equals 212 °F. This all-in-one unit conversion calculator covers 15 categories of physical quantities, so you do not need to open a separate tool for every task. It is useful for students, engineers, cooks, travellers, designers, scientists and anyone who works with different measurement systems such as metric and imperial.
How to use this unit converter
- Choose a category such as Length, Mass, Temperature or Speed.
- Type the value you want to convert in the “From” box.
- Select the starting unit and the target unit from the drop-down lists.
- Read the result instantly. Use the swap button to reverse the conversion, or copy the answer with one click.
Supported measurement categories
Length & Distance
Millimetre, centimetre, metre, kilometre, inch, foot, yard, mile and nautical mile.
Mass & Weight
Milligram, gram, kilogram, tonne, pound, ounce, stone and carat. Also convert liquids such as water, milk, oil, ghee, honey and petrol from litres, mL or gallons to kg or lb using their density.
Temperature
Celsius, Fahrenheit and Kelvin with exact formulas.
Area & Volume
Square metre, hectare, acre, guntha, litre, millilitre, gallon, cup and cubic metre.
Speed & Time
m/s, km/h, mph, knots, Mach, seconds, minutes, hours, days and years.
Data Storage
Bits, bytes, KB, MB, GB, TB, PB and binary units such as KiB, MiB and GiB.
Pressure, Energy & Power
Pascal, bar, psi, atm, joule, calorie, kWh, BTU, watt and horsepower.
Force, Angle, Frequency & Fuel
Newton, lbf, degrees, radians, hertz, rpm, km/L, L/100 km and mpg.
Common conversion chart
| Conversion | Result |
|---|---|
| 1 inch to centimetres | 2.54 cm |
| 1 foot to metres | 0.3048 m |
| 1 mile to kilometres | 1.609344 km |
| 1 kilogram to pounds | 2.204623 lb |
| 1 ounce to grams | 28.349523 g |
| 1 litre to US gallons | 0.264172 gal |
| 1 acre to square metres | 4,046.8564 m² |
| 1 acre to guntha | 40 guntha |
| 1 guntha to square feet | 1,089 ft² |
| 100 km/h to mph | 62.137119 mph |
| 1 bar to psi | 14.503774 psi |
| 1 kWh to joules | 3,600,000 J |
Frequently asked questions
Is this unit converter free to use?
Yes. The tool is completely free, works in your browser and needs no registration or download.
How accurate are the conversions?
The tool uses internationally accepted conversion factors and shows up to 10 significant digits, so results are accurate enough for school, work and technical use.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 and add 32. For example, 25 °C × 9/5 + 32 = 77 °F. The converter does this automatically.
What is the difference between MB and MiB?
One megabyte (MB) is 1,000,000 bytes, while one mebibyte (MiB) is 1,048,576 bytes. Operating systems often show MiB but label it as MB.
Does it work on mobile phones?
Yes. The layout is fully responsive and works on phones, tablets and desktop computers.