Compare two numbers and see exactly how much one has changed relative to the other. Enter an old value and a new value, and the calculator returns the percentage change, telling you clearly whether it is an increase or a decrease, along with the raw difference between the two figures. This is the calculation behind price changes, revenue growth, population shifts, test-score improvements and countless everyday comparisons, and it is easy to get backwards when done by hand. The percentage is always measured against the original value, which is the correct convention. Enter your two numbers and the answer appears instantly, with the sign making the direction unmistakable. Everything is computed locally in your browser and nothing is stored.