Three percentage questions, one tool
Most percentage problems are one of three: finding a percentage of a number, working out what percentage one number is of another, or measuring the change between two values. Rather than remember which way to divide each time, pick the question here and enter your numbers.
Instant and private
The answer updates as you type, so it doubles as a quick sanity check on a figure someone has quoted you. It all runs on your device — nothing you enter leaves the page.