Percentage Calculator
% of a number · % change · % difference · X is what % of Y · Free · Instant · No signup
What is X% of Y?
How Each Calculation Works
| Mode | Formula | Example |
|---|---|---|
| % of a number | Result = Y × X ÷ 100 | 25% of 200 = 50 |
| % change | (New − Old) ÷ |Old| × 100 | From 80 to 100 = +25% |
| % difference | |X − Y| ÷ ((|X| + |Y|) ÷ 2) × 100 | Between 80 and 100 = 22.22% |
| X is what % of Y? | X ÷ Y × 100 | 50 is 25% of 200 |
Common Percentage Calculations
| Scenario | Calculation | Answer |
|---|---|---|
| 20% tip on a £45 restaurant bill | 20% of 45 | £9.00 |
| VAT (20%) on a £150 item | 20% of 150 | £30.00 |
| 15% off a £80 jacket | 15% of 80 → subtract from 80 | £68.00 |
| Pay rise from £28,000 to £31,000 | % change from 28000 to 31000 | +10.71% |
| Test score: 47 out of 60 | 47 is what % of 60 | 78.33% |
| Price drop from £320 to £259 | % change from 320 to 259 | −19.06% |
Frequently Asked Questions
What is the difference between percentage change and percentage difference?
Percentage change has a direction — it measures how a value moves from a starting point to a new value, and can be positive (increase) or negative (decrease). Percentage difference is symmetric — it measures how far apart two values are relative to their average, so it is always positive and does not imply one value came before the other.
How do I calculate VAT from a VAT-inclusive price?
If a price already includes 20% VAT, the VAT amount is not simply 20% of the total. Instead, divide the total by 1.2 to get the pre-VAT price, then subtract. For example, a £120 VAT-inclusive price contains £20 VAT (120 ÷ 1.2 = 100; 120 − 100 = 20). You can use the '% of' mode: enter 20% of 100 to verify the VAT on the ex-VAT amount.
Why is percentage difference different from percentage change?
Because percentage difference uses the average of both values as the denominator, whereas percentage change uses only the starting value. For the pair 80 and 100: % change (from 80 to 100) = 25%, but % difference = 22.22%. Neither is wrong — they answer different questions.
How do I reverse a percentage — e.g. find the original price before a discount?
If a price was reduced by 30% to reach £140, the original was £140 ÷ 0.70 = £200. In general: original = reduced price ÷ (1 − discount rate). You can verify using the '% change' mode: % change from 200 to 140 should equal −30%.
Is my data stored anywhere?
No. All calculations run entirely in your browser using JavaScript. Nothing is sent to any server.
Can I calculate percentage of a percentage?
Yes — use the '% of' mode twice. For example, 15% of 40%: first find 40% of your number, then find 15% of that result. Or calculate directly: 15% of 40% = 0.15 × 0.40 = 0.06 = 6%.