Percentage Calculator
Three percentage calculators on one page — all update as you type.
1
What is X% of Y?
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2
X is what percent of Y?
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3
Percentage change from X to Y
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Quick reference — common percentages of 100
| Percentage | Of 100 | Of 200 | Of 500 | Of 1,000 |
|---|---|---|---|---|
| 1% | 1 | 2 | 5 | 10 |
| 5% | 5 | 10 | 25 | 50 |
| 10% | 10 | 20 | 50 | 100 |
| 15% | 15 | 30 | 75 | 150 |
| 20% | 20 | 40 | 100 | 200 |
| 25% | 25 | 50 | 125 | 250 |
| 50% | 50 | 100 | 250 | 500 |
| 75% | 75 | 150 | 375 | 750 |
How to Calculate Percentages
Finding X% of Y — multiply Y by X divided by 100. Example: 15% of 80 = 80 × 0.15 = 12.
Finding what percent X is of Y — divide X by Y and multiply by 100. Example: 12 is what percent of 80? (12 ÷ 80) × 100 = 15%.
Percentage change — subtract the original from the new value, divide by the original, multiply by 100. Example: from 80 to 92 = ((92 − 80) ÷ 80) × 100 = +15%. A positive result is an increase, negative is a decrease.
Frequently Asked Questions
Find 10% by moving the decimal point one place left, then add half of that for the extra 5%. Example: 15% of $48 = 10% ($4.80) + 5% ($2.40) = $7.20. For tip calculations, this is the fastest mental math approach.
No — this is a common misconception. A 50% increase on 100 gives 150. A 50% decrease on 150 gives 75 — not 100. Percentage changes are calculated on the current value, not the original, so they are not symmetric. Try it in calculator 3 above: from 100 to 150 (+50%), then from 150 to 75 (−50%).