Percentage Calculators
Solve any percentage question — instantly, with the math shown.
These free percentage calculators cover every everyday percent question: what is X% of a number, what percent one number is of another, the increase or decrease from one value to another, and the percentage difference between two numbers. Each tool shows its formula and a worked example, so you can check the result by hand rather than take it on faith.
A percentage is just a scaled fraction — “per hundred” — which is why the same simple arithmetic underlies discounts, tips, taxes, test scores, and statistics. Every calculation runs entirely in your browser, so the numbers you enter never leave your device.
4 percentage calculators
Percentage Calculator
Work out any percentage instantly — three calculators in one.
Percentage Increase Calculator
Add a percentage to a number, or find the percent increase between two values.
Percentage Decrease Calculator
Subtract a percentage from a number, or find the percent decrease between two values.
Percentage Difference Calculator
Find the percentage difference between two values, relative to their average.
Guides
Percentage Increase vs Decrease: Why They Don't Cancel Out
A percentage increase and the same percentage decrease don't return you to where you started. Here's why, with the formulas, worked examples, and how to reverse a percentage change correctly.
2 min read
How to Calculate Percentages: A Complete Guide
Learn how to calculate percentages step by step: percent of a number, what percent one number is of another, and percentage change — with worked examples and a quick reference.
3 min read
Frequently asked questions
Which percentage calculator should I use?
Use the Percentage Calculator for the three core questions (percent of a number, what percent one number is of another, and percentage change). The Percentage Increase and Percentage Decrease calculators each focus on a single direction; the Percentage Difference Calculator compares two values symmetrically; and the Percent Error Calculator compares a measured value to a known true value.
What is the basic percentage formula?
To find a percentage of a number, multiply by the percent divided by 100. To find what percent one number is of another, divide the part by the whole and multiply by 100. For percentage change, divide the difference by the original value and multiply by 100.
Are these percentage calculators free and private?
Yes. Every tool is free with no sign-up, and all calculations run locally in your browser — nothing you enter is uploaded or stored.
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