How to Use the Percentage Calculator
Choose the calculation type that matches your question — percentage of a number, what percent one number is of another, or percentage change — then enter the relevant values; the calculator applies the correct formula for that specific type automatically.
The Percentage Calculator covers all three common percentage question types in one tool — here's how to pick the right mode.
Choosing the right mode
If you're asking "what is X% of Y," use the percentage-of-a-number mode. If you're asking "X is what percent of Y," use the part-of-whole mode. If you're comparing an old and new value, use the percentage-change mode — picking the mode that matches your actual question is what prevents the most common percentage mistakes.
Double-checking which value is 'old' in a change calculation
For percentage change specifically, make sure the original (starting) value is entered in the correct field — most calculators label this explicitly, since entering the values in the wrong order is the most common source of an incorrect percentage-change result.