Free Unit Converter

What Is a Unit Converter?

A unit converter is a free online tool that instantly converts values between different measurement units across five categories: length (mm, cm, m, km, inches, feet, yards, miles), weight (mg, g, kg, metric tons, ounces, pounds), temperature (Celsius, Fahrenheit, Kelvin), speed (km/h, mph, m/s, knots) and area (cm², m², km², in², ft², acres). Results update live as you type — no button press required.

Unit conversion is needed daily — in cooking, travel, engineering, science and fitness. Our converter covers the most common categories in one clean page, with a swap button to instantly reverse the direction of any conversion.

How to Use the Unit Converter - Step by Step

1. 1

   Select a category

   Choose from Length, Weight, Temperature, Speed or Area using the category tabs at the top.

2. 2

   Enter your value

   Type a number in the input field. The result updates instantly as you type.

3. 3

   Choose From and To units

   Select the source unit and the target unit from the dropdowns. Use the Swap button to reverse them.

Frequently Asked Questions - Unit Converter

How do I convert km to miles?

Select Length, enter your km value, set From = Kilometres and To = Miles. 1 km = 0.621371 miles.

How do I convert Celsius to Fahrenheit?

Select Temperature, enter your °C value, set From = Celsius and To = Fahrenheit. The formula is °F = (°C × 9/5) + 32.

How do I convert kg to lbs?

Select Weight, enter your kg value, set From = Kilograms and To = Pounds. 1 kg = 2.20462 lbs.

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