Percentage Calculator
Use this free percentage calculator to instantly solve the most common percentage problems — find what percent one number is of another, calculate percentage change, or work out a percentage of any value. No formula knowledge needed — just enter your numbers and get an instant answer.
% Percentage Calculator
How to Use the Percentage Calculator
- Select the type of percentage calculation you need
- Enter your values in the fields provided
- Click Calculate for an instant answer with a step-by-step explanation
Types of Percentage Calculations
1. What is X% of Y?
To find a percentage of a number, multiply the number by the percentage and divide by 100.
Formula: Result = (Y × X) ÷ 100
Example: What is 20% of 150? → 150 × 20 ÷ 100 = 30
2. X is what % of Y?
To find what percentage one number is of another, divide the first number by the second, then multiply by 100.
Formula: Percentage = (X ÷ Y) × 100
Example: 30 is what % of 150? → (30 ÷ 150) × 100 = 20%
3. Percentage change (increase or decrease)
To find the percentage change between two values, subtract the original from the new value, divide by the original, and multiply by 100.
Formula: % Change = ((New − Old) ÷ Old) × 100
Example: Price goes from £80 to £100 → ((100 − 80) ÷ 80) × 100 = 25% increase
Common Percentage Examples
| Problem | Calculation | Answer |
|---|---|---|
| 10% of 200 | 200 × 10 ÷ 100 | 20 |
| 25% of 80 | 80 × 25 ÷ 100 | 20 |
| 15% of 350 | 350 × 15 ÷ 100 | 52.50 |
| 40 is what % of 200? | (40 ÷ 200) × 100 | 20% |
| % change from 50 to 75 | ((75−50) ÷ 50) × 100 | 50% increase |
| % change from 100 to 85 | ((85−100) ÷ 100) × 100 | 15% decrease |
| VAT at 20% on £250 | 250 × 20 ÷ 100 | £50 VAT (£300 total) |
| Tip of 15% on £45 | 45 × 15 ÷ 100 | £6.75 |
Real-World Uses for a Percentage Calculator
- Shopping: Calculate how much you save in a sale (e.g. 30% off £120 = saving £36)
- Finance: Work out interest rates, investment returns, or tax amounts
- School and work: Convert test scores into percentages or track progress
- Business: Calculate profit margins, markups, and percentage growth
- Cooking: Scale recipes up or down by a percentage
- Health: Track body weight loss as a percentage of starting weight
Percentage Calculator FAQ
How do I calculate a percentage?
Divide the part by the whole and multiply by 100. For example, if 30 out of 120 students passed, the percentage is (30 ÷ 120) × 100 = 25%.
How do I add a percentage to a number?
Multiply the number by (1 + percentage/100). For example, to add 20% to £50: 50 × 1.20 = £60. Or use our percentage increase calculator for instant results.
How do I subtract a percentage from a number?
Multiply the number by (1 − percentage/100). For example, to subtract 15% from £200: 200 × 0.85 = £170. Or use our percentage decrease calculator.
What is the difference between percentage and percentile?
A percentage is a proportion expressed out of 100 (e.g. 75%). A percentile is a value below which a given percentage of observations fall — used in statistics, test scores, and growth charts. For example, scoring in the 90th percentile means you scored higher than 90% of people.
Related Calculators
- Percentage Increase Calculator — Calculate the % growth between two numbers
- Percentage Decrease Calculator — Calculate the % drop between two numbers
- Discount Calculator — Find the final price after any discount
- VAT Calculator — Add or remove VAT from any price
- ROI Calculator — Calculate return on investment as a percentage