Calculate percentages instantly — what percent, increase, decrease, and difference.
A percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign (%). Percentages are used widely in everyday life — from calculating discounts and taxes to measuring growth rates and exam scores. The word "percent" comes from the Latin phrase "per centum," meaning "by the hundred."
The Percentage Calculator by Calculator Expert makes it easy to solve the four most common percentage problems: finding a percentage of a number, calculating percentage increase or decrease, finding the percentage difference between two values, and determining what percent one number is of another. All calculations are instant, accurate, and shown with step-by-step formulas.
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/2 | 0.50 | 50% |
| 1/4 | 0.25 | 25% |
| 3/4 | 0.75 | 75% |
| 1/5 | 0.20 | 20% |
| 1/10 | 0.10 | 10% |
| 1/3 | 0.333 | 33.33% |
| 2/3 | 0.667 | 66.67% |
| 1/8 | 0.125 | 12.5% |
Select the type of percentage calculation you need using the tabs at the top. Enter your values in the input fields and click "Calculate." The result appears instantly along with the formula used. All input fields are empty so you can enter your own values freely.
Method 1 – Proportion Method: Set up a proportion where the percentage is a ratio of the part to the whole multiplied by 100. This is the most common textbook method.
Method 2 – Decimal Method: Convert the percentage to a decimal by dividing by 100, then multiply. For example, 30% of 150 = 0.30 × 150 = 45.
Method 3 – Cross Multiplication: Used when finding what percent X is of Y. Set up X/Y = ?/100 and solve for ?.
This calculator works with numerical values only. Division by zero is avoided and will produce an error message. For very large or very small numbers, scientific notation may appear in the result. Percentage calculations are mathematical and do not account for rounding rules used in finance or accounting — always verify critical financial figures with a certified accountant.
In medical contexts, percentages are used to express body composition metrics like body fat percentage. Unlike the Ponderal Index (which uses weight/height³), body fat percentage represents the proportion of fat mass to total body mass and is expressed as a standard percentage.
Percentage calculations are used in exam score analysis, discount and sale price computation, tax calculations (GST, income tax), profit and loss in business, interest rate calculations in banking, population growth analysis, and nutritional information on food labels.