Percentage Calculator
Three percentage calculators in one: find a percentage, find what percentage a number is, and calculate percentage increase or decrease.
What is X% of Y?
How to use Percentage Calculator
The percentage calculator covers three essential percentage operations in one tool: (1) What is X% of Y? (2) X is what percent of Y? (3) What is the percentage change from X to Y? Each panel shows both the answer and the formula used, making it useful for mental-maths checking, grade calculations, discount calculations and financial growth analysis.
- Choose the calculation type using the tab at the top.
- Enter the two numbers for your chosen operation.
- The answer and formula appear instantly.
- Copy the result with the copy button.
Your data never leaves your device — 100% private processing.
Three percentage operations explained
Percent of: (X/100) × Y = result. Useful for calculating tips, discounts and tax. What percent: (X/Y) × 100 = result%. Useful for grade calculations, market share and composition ratios. Percentage change: ((new − old) / old) × 100 = change%. Positive values are increases; negative values are decreases. A drop from 100 to 50 is −50%; a rise from 50 to 100 is +100% — demonstrating that percentage changes are asymmetric.
Percentage points vs percentages
A rise from 10% to 15% is 5 percentage points (absolute difference) but 50% (relative change). Confusing these is extremely common in financial and political reporting. When a central bank raises rates "by 25 basis points" it means 0.25 percentage points (one basis point = 0.01%). When a politician claims "crime fell 50%", verify whether they mean a 50-percentage-point fall or a 50% relative change — the latter is far more common.
| Scenario | Original | New value | Result |
|---|---|---|---|
| 10% of 500 | 500 | — | 50 |
| What % is 45 of 180? | 180 | 45 | 25% |
| Change from 80 to 100 | 80 | 100 | +25% |
| Change from 100 to 80 | 100 | 80 | −20% |
| 15% tip on $60 | $60 | — | $9 |
Glossary
- Percentage point
- An absolute difference between two percentages; a rise from 10% to 15% is 5 percentage points, not 50%.
- Basis point
- One hundredth of a percentage point (0.01%), used in finance and interest rates.
- Relative change
- A percentage expressing how much a value changed relative to the original value.
- Absolute change
- The raw numerical difference between two values.
Related reading
Frequently Asked Questions
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Why use Percentage Calculator?
- Step-by-step explanations alongside every calculation
- Printable or shareable result summaries
- Works entirely offline in your browser
- Built-in input validation prevents common mistakes
Common use cases
- Calculate loan repayments before applying
- Check compound interest on savings accounts
- Estimate tax owed before filing
- Work out break-even point for a new business
- Plan retirement savings contributions
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