Percentage Calculator
Find a percent of a number, a ratio, and a percentage change in one place — the three percentage calculations you use most, from discounts to tax to scores.
All three modes need just two numbers. Everything runs in your browser.
What is a percentage?
Percent (%) means 'per hundred'. 25% is 25 out of 100. It shows up everywhere — discounts, tax, scores, interest, gains and losses — but it gets confusing because the answer depends on what you treat as the base. Master three calculations and you cover almost every case.
The three calculations
- X% of a number: number × X ÷ 100. e.g. 18% of 1,200 = 216.
- What percent one number is of another: part ÷ whole × 100. e.g. 45 ÷ 180 × 100 = 25%.
- Percentage change: (new − old) ÷ old × 100. e.g. 200 → 250 is +25%.
Where it helps
- Shopping: subtract a discount from the list price to see the final price.
- Tax: add a VAT/GST rate to a net price, or back it out of a total.
- Scores: divide correct answers by the total for a percentage score.
- Investing: see how much a price rose or fell versus your entry.
Common mistakes
- Percentage change is always measured against the OLD value, not the new one.
- 'Percentage points' and 'percent' differ. Going from 20% to 25% is 5 points but a 25% increase.
- A 20% discount then a 20% markup does not return the original price, because the base changes.
The numbers you enter are calculated in your browser and never sent to a server.
Read the Privacy Policy →Frequently asked questions
How do I find a percent of a number?
Multiply the number by the percent and divide by 100. For example, 18% of 1,200 is 1,200 × 18 ÷ 100 = 216.
How do I know what percent one number is of another?
Divide the part by the whole and multiply by 100. 45 ÷ 180 = 0.25, times 100 = 25%.
How do I calculate an increase or decrease?
(new − old) ÷ old × 100. A positive result is an increase, negative is a decrease. 200 to 250 is +25%; 250 to 200 is −20%.
What's the difference between percentage points and percent?
A rate going from 3% to 5% is a '2 percentage point' rise, but about a 67% increase in relative terms. Absolute gaps use points; relative change uses percent.
Are my inputs stored?
No. All calculations run in your browser and nothing is sent to or stored on a server.