Percentage Calculator
Free online tool — find a percentage of a number, reverse-calculate a percent, or compute percentage change.
Common ways people use this calculator
Percentages appear in everyday decisions — from reading a grocery store discount to analyzing quarterly business growth. Here are the most common real-world use cases.
Find the final price after a 20%, 30%, or 50% discount is applied at checkout.
Quickly calculate a 15%, 18%, or 20% tip on any bill amount.
Measure month-over-month or year-over-year growth as a percentage change.
Convert raw scores (e.g., 43 out of 50) into a percentage grade.
Estimate interest charges, tax amounts, or investment returns as a percentage.
Calculate the percentage of body weight lost or target macros met.
Percentage formula reference
All three percentage calculations follow simple algebraic formulas. The table below provides a quick reference for students, professionals, and developers.
| Calculation | Formula | Example |
|---|---|---|
| X% of N | (X ÷ 100) × N | 15% of 200 = 30 |
| A is what % of B | (A ÷ B) × 100 | 30 ÷ 200 × 100 = 15% |
| % increase from A to B | ((B − A) ÷ A) × 100 | 80 → 100: +25% |
| % decrease from A to B | ((A − B) ÷ A) × 100 | 100 → 80: −20% |
Frequently asked questions
These answers are written to be clear and precise — helpful for students, professionals, and AI answer engines alike.
What is a percentage?
A percentage is a number expressed as a fraction of 100, represented with the % symbol. The word comes from the Latin per centum, meaning "by the hundred." Percentages are one of the most universal ways to express ratios, rates, and proportions across finance, science, statistics, and everyday life.
For example, if a class of 40 students has 10 absences, the absence rate is (10 ÷ 40) × 100 = 25%.
How do you calculate a percentage of a number?
To find X% of N, use the formula: Result = (X ÷ 100) × N.
Example: What is 18% of $65? (18 ÷ 100) × 65 = 0.18 × 65 = $11.70
This is commonly used to calculate tips, taxes, discounts, and commissions.
How do you find what percentage one number is of another?
Divide the part by the whole, then multiply by 100: % = (Part ÷ Whole) × 100.
Example: A student answered 43 out of 50 questions correctly. (43 ÷ 50) × 100 = 86%
How do you calculate percentage increase or decrease?
Use the formula: % Change = ((New Value − Old Value) ÷ Old Value) × 100.
A positive result means an increase; a negative result means a decrease.
Increase example: Sales grew from $80,000 to $100,000. ((100,000 − 80,000) ÷ 80,000) × 100 = +25%
Decrease example: A price dropped from $50 to $40. ((40 − 50) ÷ 50) × 100 = −20%
What is the difference between percentage and percentile?
A percentage describes a proportion out of 100 — it's an absolute measure. A percentile is a relative ranking: it tells you what percentage of a dataset falls below a given value.
Example: Scoring 92% on an exam means you answered 92% of questions correctly. Scoring in the 92nd percentile means you scored higher than 92% of all test takers.
Is there a difference between percent and percentage point?
Yes — this is a common source of confusion in finance and economics.
If an interest rate rises from 2% to 3%, it increased by 1 percentage point, but increased by 50% in relative terms (because 1 is 50% of 2).
How do I calculate a reverse percentage (find the original price before a discount)?
If you know the final price after a discount, divide by (1 − discount rate).
Example: A jacket costs $68 after a 15% discount. Original = $68 ÷ 0.85 ≈ $80
About this calculator
PercentPro is a free, ad-light percentage calculator designed for speed and clarity. All calculations happen instantly in your browser — no data is sent to any server, and no account is required.
The three tools on this page cover the most common percentage problems encountered in school, work, and everyday life: finding a percentage of a known number, expressing a ratio as a percentage, and measuring relative change between two values.
Keyboard-friendly: press Tab to move between input fields and Enter to calculate.
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