This calculator handles the three percentage questions you reach for most: what is X% of Y, X is what percent of Y, and the percentage change from one number to another. Each updates instantly in your browser.
How to use it
- Pick the calculation you need.
- Enter the numbers.
- The result appears instantly.
About Percentage Calculator
Percentages come up constantly — discounts, tax, tips, growth rates, test scores, statistics. The mental arithmetic is simple in principle but easy to slip on, especially percentage change, where people often mix up the base. This calculator lays out the common percentage questions clearly so you get the right answer without second-guessing the formula. It runs entirely in your browser.
FAQ
How is percentage change calculated?
As (new − old) ÷ old × 100. A positive result is an increase; a negative result is a decrease.
What is the difference between the three modes?
One finds a percentage of a number, one finds what percent one number is of another, and one finds the change between two numbers.
How do I calculate percentage change?
Percentage change is (new value minus old value) divided by the old value, times 100. A rise from 80 to 100 is a 25% increase; a drop from 100 to 80 is a 20% decrease. This tool handles all the common percentage questions.