About this tool
This percentage calculator quickly answers the common "what percent" questions: what percent one number is of another, what you get after increasing or decreasing a number by a percentage, and the growth or drop rate between two numbers. It takes the easy-to-confuse ratio math off your hands and gives the answer in one step.
It fits everyday situations — shopping discounts, test score rates, data growth, salary raises — computing locally and instantly, with no formulas to memorize.
How to use
- Pick the type of calculation (e.g. "X is what percent of Y", "X increased by N%").
- Enter the known numbers in the matching fields.
- The tool returns the result instantly.
- Switch the calculation type as needed for a different percentage problem.
When to use it
- Work out the final price and savings on a discounted purchase.
- Compute a test or survey score rate and accuracy.
- Compare growth or decline rates between two periods of data.
- Check salary raises, interest rates and commission percentages.
FAQ
How is the growth rate calculated?
Growth rate = (new − old) ÷ old × 100%. A positive result is an increase, a negative one is a decrease.
Why does "+20% then −20%" not return to the original?
Because the two percentages use different bases: the increase is on the original, the decrease is on the larger increased number, so the result ends slightly below the original.
Are decimals kept?
Decimals are kept as needed; you can read the full result and round it yourself.