A percentage expresses a number as a fraction of 100. The word comes from the Latin per centum — "by the hundred." Percentages are used everywhere: VAT rates, interest rates, sale discounts, exam scores, pay rises, body fat measurements and nutritional labels all use percentage.
This calculator covers the three calculations people need most. Use "What is X% of a number?" for tips, discounts and tax. Use "What percentage is X of Y?" to find what score you got or what proportion you've completed. Use "Percentage change" to see how much something has increased or fallen.
Percentage calculations appear throughout financial tools: use the Discount Calculator for sale prices, the VAT Calculator to add or remove tax, and the Tip Calculator to calculate gratuity as a percentage of the bill.
How to use the Percentage Calculator
1
Choose a calculation type — select the card that matches what you need
2
Enter your values — type the numbers into both input fields
3
Tap Calculate — the result appears instantly
4
Try another type — all three calculators are available below
Common percentages at a glance
A quick reference for some common percentages of 100, 250 and 1000. For any percentage of any number, use the first calculator above.
Percent
of 100
of 250
of 1000
5%
5
12.5
50
10%
10
25
100
15%
15
37.5
150
20%
20
50
200
25%
25
62.5
250
50%
50
125
500
Frequently Asked Questions
Enter 20 in the percentage field and your number in the second field under "What is X% of a number?" then tap Calculate.
Use the "Percentage change" card. Enter the original value and the new value — the result shows the increase or decrease.
Yes — enter any decimal and the result is shown to 2 decimal places.
Multiply the original price by 0.20 to find the discount amount, then subtract. For example: £80 × 0.20 = £16 discount → £64 sale price. Or use the Discount Calculator for a full breakdown with multiple percentages.
A percentage point is an absolute difference between two percentages. If interest rates rise from 3% to 5%, that is a 2 percentage point increase — but a 66.7% increase in the rate itself. This distinction matters in finance and economics.
If a discounted price is £72 after a 10% reduction, the original price was £72 ÷ 0.90 = £80. For any percentage reduction: original = sale price ÷ (1 − discount rate). This is the reverse percentage calculation.
Divide the percentage by 100, then multiply by the number. For example, 20% of 150 is 0.20 × 150 = 30. The first calculator above does this instantly.