Percentage Calculator
Calculate percentages instantly — find X% of Y, percentage change, and more. Free, no signup.
Instantly calculate X% of Y, percentage change, or add/subtract percentages.
Four calculation modes — no signup, no ads.
What is X% of Y?
X is what % of Y?
Percentage Change
Add / Subtract %
What Percentages Actually Are
"Percent" comes from the Latin per centum — per hundred. When you say "25%," you mean 25 out of every 100. That's it. Every percentage problem boils down to dividing something into 100 equal parts and counting how many you're talking about.
This simplicity is why percentages show up everywhere: tax rates, exam scores, battery levels, interest rates, sale prices, tip amounts, nutritional labels. They're the universal language for "how much of the whole."
The four calculations above cover every percentage problem you'll encounter in daily life. "What is X% of Y" handles discounts and tips. "X is what % of Y" handles grades and proportions. Percentage change handles price movements and growth. Add/subtract percentage handles VAT and markups.
Mental Maths Shortcuts
| To Find | Shortcut | Example |
|---|---|---|
| 10% | Move the decimal one place left | 10% of £85 = £8.50 |
| 5% | Find 10%, then halve it | 5% of £85 = £4.25 |
| 15% | Find 10% + 5% | 15% of £85 = £8.50 + £4.25 = £12.75 |
| 20% | Find 10%, then double it | 20% of £85 = £17.00 |
| 25% | Divide by 4 | 25% of £85 = £21.25 |
| 33% | Divide by 3 | 33% of £85 ≈ £28.33 |
| 50% | Halve the number | 50% of £85 = £42.50 |
| 1% | Move the decimal two places left | 1% of £85 = £0.85 |
What this means for you: You can calculate any percentage by combining these building blocks. Need 17.5%? That's 10% + 5% + 2.5%. Need 12%? That's 10% + 1% + 1%. Once you master 10% and 1%, every other percentage is just addition.
Percentage Change vs Percentage Points
This trips up even financial professionals. If a mortgage rate goes from 4% to 5%, it rose by 1 percentage point but by 25% in relative terms (because 1 is 25% of 4). Both statements are true, but they mean very different things.
| Change | Percentage Points | Percentage Change | Why It Matters |
|---|---|---|---|
| Interest rate 2% → 4% | +2 pp | +100% | Your repayments literally doubled |
| Tax rate 20% → 25% | +5 pp | +25% | You keep less of each pound earned |
| Inflation 10% → 3% | −7 pp | −70% | Prices still rising, just more slowly |
What this means for you: When news headlines say "inflation fell 2%," check if they mean 2 percentage points (meaningful) or 2% of the current rate (minor). The percentage change calculator above gives you the relative change — which is usually what matters for your wallet.
Common Percentage Mistakes
Reversing a Percentage
If a price rises 20% then falls 20%, you're NOT back where you started. £100 + 20% = £120. Then £120 − 20% = £96. You've lost £4. The base changes after each step — a common trap in investment returns.
Stacking Discounts
A 30% discount followed by a 20% discount is NOT 50% off. It's 30% off the original, then 20% off the already-reduced price. £100 → £70 → £56. You save 44%, not 50%. Use our Discount Calculator to stack discounts correctly.
Removing VAT Incorrectly
To remove 20% VAT, divide by 1.2 — do NOT subtract 20%. If an item costs £120 including VAT, the net price is £100 (£120 ÷ 1.2), not £96 (£120 − 20%). This £4 difference adds up fast on invoices.
Comparing Unequal Bases
"Company A grew 50% and Company B grew 10%" doesn't tell the full story. If A went from £1M to £1.5M and B went from £100M to £110M, B actually added 20x more revenue. Always check the absolute numbers behind percentages.
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How to use this tool
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Common uses
- Calculating sale discounts while shopping
- Working out tax amounts on invoices
- Comparing price changes over time
- Figuring out tip amounts at restaurants
- Calculating grade percentages for exams
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