Percentage Calculator
Calculate percentages, increases, decreases, changes, and reverse lookups — free, instant
6 calculators • 0 calculations
What is X% of Y?
result = (X / 100) × Y
Increase by X%
result = value + (value × X / 100)
Decrease by X%
result = value − (value × X / 100)
Percentage Difference
result = ((B − A) / A) × 100
Percentage Change
result = ((new − old) / old) × 100
X is Y% of what?
original = (result × 100) / percentage
Free Online Percentage Calculator — Six Calculators in One Tool
Percentages are everywhere — discounts, taxes, tips, test scores, investment returns, salary increases, statistics, and more. But percentage calculations can be confusing, especially when you need to work backwards or calculate change between two numbers. This free Percentage Calculator gives you six different calculation modes in one clean interface, so you can solve any percentage problem in seconds.
Each calculator shows the mathematical formula it uses, so you can understand the logic behind the result. Results are displayed instantly with one-click copy. Every calculation is logged in a scrollable history panel — you can review your past calculations or clear the history at any time.
All processing happens in your browser. There is no server, no account, no data collection. Enter your numbers, click Calculate, and get your answer immediately.
Six Percentage Calculators Explained
What is X% of Y?
The most common percentage calculation. Enter the percentage and the value, and it returns the portion. For example, 25% of 200 = 50. Used for tips, discounts, taxes, and any fraction-of-total calculation.
Increase by X%
Adds a percentage of the original value to itself. For example, 100 increased by 20% = 120. Used for price markups, salary raises, and investment growth projections.
Decrease by X%
Subtracts a percentage of the original value from itself. For example, 100 decreased by 15% = 85. Used for discounts, depreciation, and loss calculations.
Percentage Difference
Calculates the relative difference between two values as a percentage of the first value. For example, from 50 to 75 = 50%. Used for comparing prices, scores, and performance metrics.
Percentage Change
Calculates how much a value has changed relative to its original. Shows positive (+) or negative (−) direction. Used for financial returns, growth rates, and before/after comparisons.
X is Y% of what? (Reverse)
Works backwards to find the original value when you know the result and the percentage. For example, if 50 is 25% of something, the answer is 200. Used for finding totals from partial information.
When to Use a Percentage Calculator
Shopping and discounts
Calculate the final price after a percentage discount. If a $150 item is 30% off, use the Decrease calculator: 150 − 30% = $105.
Restaurant tips
Calculate 15%, 18%, or 20% of your bill. Use the Basic calculator: 20% of $85 = $17 tip.
Salary and raise calculations
If your salary is $60,000 and you get a 7% raise, use the Increase calculator: $60,000 + 7% = $64,200.
Tax calculations
Calculate sales tax, VAT, or income tax on a purchase or salary. Use the Basic calculator to find the tax amount, or the Increase calculator to find the total with tax included.
Investment returns
If your portfolio went from $10,000 to $12,500, use the Percentage Change calculator to find the return: +25%.
Academic grading
Find what percentage you scored on a test. If you got 42 out of 50, use the Basic calculator in reverse: (42/50) × 100 = 84%.