Free Online Unit Converters
Welcome to Online Conversion — your all-in-one resource for fast and accurate unit conversions. Whether you're working on a school project, recipe, scientific task, or just curious, we’ve got a tool to convert anything from length, weight, temperature, volume, and more. Our tools are easy to use, optimized for all devices, and updated regularly to ensure precision. Scroll down and explore our most popular converters by category.
Length Conversions
Temperature Conversions
Weight Conversions
Volume Conversions
Why Use Online Unit Converters?
Manual conversions can be time-consuming and error-prone. Our online unit converters eliminate the need for memorizing formulas or double-checking math. Simply input a value and get the result instantly — with support for both directions, whether you're converting kilometers to miles or Fahrenheit to Celsius.
Our tools cover a wide range of categories including:
- Length: meters, feet, inches, kilometers, miles
- Weight: kilograms, pounds, ounces, stones
- Temperature: Celsius, Fahrenheit, Kelvin, Rankine
- Volume: liters, gallons, cups, milliliters
Whether you’re a student, professional, traveler, or home cook, these tools are designed to be fast, accessible, and 100% free. We’re here to make everyday tasks simpler.
Accurate, Fast, and Mobile-Friendly
All our converters are mobile-friendly and load instantly. We use real conversion factors with up-to-date formulas so you always get reliable results. The responsive design ensures a seamless experience on both desktop and mobile devices.