This converter moves a number between the units people actually have to reconcile: a recipe in cups against a kitchen scale in grams, a height in feet against a form that wants centimetres, a hard drive quoted in TB against a folder measured in GB. It covers length, weight, temperature, area, volume, speed, data and time, and shows the value in every unit of the category at once, so you can read off the one you need without converting twice. It runs in the page — no request goes out when you type.
Because its scales do not start at the same place. Ten metres is ten times one metre, but ten degrees Celsius is not ten times one degree — zero means something different on each scale. Temperature is converted with the proper formula rather than by multiplying.
1,024. This tool uses the binary steps that operating systems and file managers report, so the numbers match what you see on your own disk. Drive manufacturers use 1,000, which is why a 1 TB drive shows up as about 931 GB.
The US liquid gallon of 3.785 litres and the US cup of about 237 millilitres. The imperial gallon used in the UK is roughly 4.546 litres, so a recipe written in one is not interchangeable with the other.
Because the exact conversion needs them. The result keeps enough digits to stay accurate for the size of the number, and switches to scientific notation when the value gets very large or very small. Copy what you need and round it yourself.
A traditional East Asian unit of area still used for property in Korea, equal to about 3.3 square metres. It is included because apartment listings there are quoted in pyeong while official documents use square metres.