Percentage Calculator
5 modes for everyday percentage math
Quick guide
What can Percentage Calculator help you do?
Free percentage calculator with 5 modes: of, ratio, change, increase, decrease.
Best for
Use five modes for discounts, budget shares, growth rates, and values after an increase or decrease. It applies arithmetic, not tax or rate rules.
How to use it
Select the matching mode and fill both fields. Use X% of Y for 15% of 1,200, Change for 80 to 100, or Decrease by 20% for an 80%-price sale.
How to read the result
Adding 20% then subtracting 20% changes 100 to 96. From 5% to 6% is 1 percentage point but a 20% relative rise.
Privacy and limits
Both numbers and the mode stay in this browser and are not uploaded or sent. Use sample values for confidential figures.
Change divides by the starting value, so zero has no rate. Cuts above 100% still follow the formula.
Frequently Asked Questions
Why doesn't +10% then -10% return to original?
Because the 10% decrease is applied to the larger value. 100 → 110 → 99.