A percentage calculator for everyday decisions
Use this calculator for discounts, sales tax, tips, markups, growth rates, and quick comparisons. Results update while you type, so it is easy to test different scenarios.
Common examples
| Question | Calculation |
|---|---|
| What is 15% of 200? | 30 |
| Add 8% tax to 125 | 135 |
| Take 25% off 80 | 60 |
| Change from 50 to 65 | 30% increase |
Percentage change formula
Percentage change is (new − original) ÷ |original| × 100. The original value cannot be zero because division by zero is undefined.
Useful tip
For financial decisions, keep more precision during the calculation and round only the final amount. This avoids small differences when several percentages are applied in sequence.
Frequently asked questions
Does the calculator support decimals?
Yes. Both inputs accept decimal and negative values.
Why can’t percentage change start at zero?
A percentage change uses the original value as the divisor, so a zero starting value has no defined percentage change.