Seventeen simple tools for the numbers that come up every day — tips, percentages, loans, VAT, savings, debt, margin, fuel cost, BMI and more. Pick one to get started.
This percentage calculator answers the everyday question “what is X% of Y?” Use it for discounts, taxes, tips, test scores, commissions, interest and statistics. Enter the percentage and the number, and the result appears instantly.
To find a percentage of a number, divide the percentage by 100 and multiply by the number. For example, 15% of 200 = (15 ÷ 100) × 200 = 30. The calculator does this for you automatically.
25% of 640 is 160. 8% of 150 is 12. Change either field and the answer recalculates in real time.
To find a percentage change, subtract the old value from the new, divide by the old value, and multiply by 100. A rise from 80 to 100 is a 25% increase, while a fall from 100 to 80 is a 20% decrease — the base is different, which is why the two figures do not match.
If 30 is 15% of a number, divide 30 by 0.15 to get 200. Reverse percentages help you find an original price before a discount or a total before tax.
The same operation — part = whole × percent ÷ 100 — covers tips, sales tax, VAT, interest, exam scores, nutrition labels and statistics. Learn it once and every percentage problem becomes the same.
To find X% of a number, the tool multiplies the number by X divided by 100 — so 20% of 150 is 150 × 0.20 = 30. A percentage is just a fraction of one hundred, which is why 50% is always half. Keep in mind that a percentage and a percentage point are different: going from 10% to 12% is a rise of two percentage points, but a 20% increase.
Sometimes you know the figure after a change and want the original. If a price of 120 already includes 20% tax, the original is 120 ÷ 1.20 = 100, not 120 minus 20%. The same trick recovers a pre-discount price: an item that cost 60 after 25% off was 60 ÷ 0.75 = 80 before. Dividing, not subtracting, is the key.
Divide the percentage by 100 and multiply by the number. 20% of 150 = 0.20 × 150 = 30.
Subtract the old value from the new, divide by the old value, then multiply by 100. From 80 to 100 is a 25% increase.
Divide the part by the whole and multiply by 100. 30 out of 120 is 25%.