Converters

The Unit Converter covers length, weight, temperature, volume, speed, area and digital storage, in metric and imperial. Temperature is the one people get wrong by hand: Celsius and Fahrenheit differ by an offset as well as a scale, so a single multiplication won’t do. Digital storage has its own trap. A kilobyte can mean 1,000 or 1,024 bytes depending on who’s counting; this converter uses 1,024.

The Color Converter translates between HEX, RGB and HSL, has a visual picker, and checks the contrast ratio between a text color and its background. It tells you whether the pair passes WCAG AA for normal text (at least 4.5:1), AA for large text (3:1) and AAA (7:1). That check matters more than the conversion. A brand color that looks fine on your monitor can still fail for body text, and the ratio tells you before a user squints at it.

Need to encode data rather than convert a measurement? The developer tools handle Base64 and URL encoding. For the color models themselves, read HEX, RGB and HSL explained.