Most versatile
Percentage Calculator
Find a percentage of a number, work out what percent one number is of another, or calculate a percentage of a percentage.
Try: What is 20% of 80?Open Percentage CalculatorFree online math calculators
Math Calculators and Tools
Choose the math calculator that matches your question. These free calculator tools cover percentages, increases, differences, changes, and discounts. Each result includes the formula and working, so it is easy to understand and check.
Math calculator directory
Choose a math calculator
Start with the general percentage tool, or pick a focused calculator when you already know the type of result you need.
Percentage Increase Calculator
Measure how much a value has increased compared with its original value.
Try: Increase from 100 to 125Open Percentage Increase CalculatorPercentage Difference Calculator
Compare two values when neither one is the starting point.
Try: Difference between 100 and 125Open Percentage Difference CalculatorPercentage Change Calculator
Calculate an increase or decrease from an old value to a new value.
Try: Change from 80 to 68Open Percentage Change CalculatorPercent Off Calculator
Find the discount amount and final sale price after a percentage is taken off.
Try: 25% off £40Open Percent Off CalculatorCalculator chooser
Match your question to the right tool
The wording of the question tells you which value should be used as the base. Choose the closest example below.
| Your question | Best calculator | What it finds |
|---|---|---|
| What is 20% of 80? | Percentage Calculator | The percentage amount |
| What percent is 12 of 60? | Percentage Calculator | One number as a percent of another |
| How much did 100 increase to 125? | Percentage Increase Calculator | The percentage increase |
| How different are 100 and 125? | Percentage Difference Calculator | The symmetric percentage difference |
| What changed from an old value to a new value? | Percentage Change Calculator | The percentage increase or decrease |
| What is the price after 25% off? | Percent Off Calculator | The discount and sale price |
How the maths works
Clear formulas, not unexplained answers
A percentage describes an amount out of 100, but the correct calculation depends on what you know. Finding 20% of 80 uses 20 ÷ 100 × 80. Finding what percent 12 is of 60 uses 12 ÷ 60 × 100.
Change questions need one more decision. Use the original value as the base when a number moves from old to new. Use the average of both values when you are comparing two numbers and neither one is the starting point.
Math guides
Learn the percentage formulas
Use the guides when you want to understand the method, check a worked example, or calculate the answer by hand.
How to Calculate Percentages
Learn the main percentage formulas, see worked examples, and choose the right method for your question.
how to calculate percentagesHow to Calculate Percentage Increase
Understand the percentage increase formula and work through old-value to new-value examples.
how to calculate percentage increasePercentage Change Formula
See how percentage change, percentage increase, and percentage difference use different reference values.
percentage change formulaCommon questions
About these math tools
A few quick answers to help you choose and check a calculation.
Which math calculator should I use?
Choose the percentage calculator for general percent questions. Use percentage increase or percentage change when you have an original value and a new value. Use percentage difference when neither value is the starting point, or the percent off calculator for discounts and sale prices.
Are these online math calculators free?
Yes. Every calculator on this page is free to use. Results update from the values you enter and include the formula and calculation steps.
What is the difference between percentage change and percentage difference?
Percentage change compares a new value with an original value and uses the original value as its base. Percentage difference compares two values without treating either one as the starting point, so it uses their average as the base.
Do the calculators show their working?
Yes. Each mathematical calculator shows the answer, the formula used, and the main steps so you can check how the result was found.