Percentage Calculator
“What's 30% off?” “How much did it grow?” “What's the price before tax?” Six everyday percentage questions on one screen.
Results update as you type. Click a result to copy it.
This tool runs entirely in your browser. Nothing you add is uploaded to any server.
Last checked: · Made by Fingertip Workshop
How to use
- 1
Change the numbers in any row — results update as you type.
- 2
Click a result to copy it without commas, ready for a spreadsheet.
Percentage formulas
| Question | Formula | Example |
|---|---|---|
| B% of A | A × B ÷ 100 | 15% of 200 = 30 |
| A is what % of B? | A ÷ B × 100 | 45 of 60 = 75% |
| % change A → B | (B − A) ÷ A × 100 | 120 → 150 = +25% |
| B% off A | A × (1 − B ÷ 100) | $89 at 30% off = $62.30 |
| Price before tax | A ÷ (1 + rate) | $110 at 10% → $100 + $10 tax |
Percent vs. percentage points
A rate going from 2% to 3% rose by 1 percentage point — or 50%. And +10% then −10% leaves you at 99%, because the base changes.
FAQ
Two discounts stacked?
20% then 10% off is 28% total, not 30% (0.8 × 0.9 = 0.72).
How do I add tax to a price?
The tax row also shows the total if tax is added on top.
How many decimals?
Results are rounded to two decimals; tax amounts to whole units.