About
This tool helps you calculate percentages quickly: percent of a number, what percent one number is of another, and the percentage change between two numbers. It is free to use and works on mobile and desktop.
How do I calculate discount percentage?
Discount percentage is calculated by dividing the discount amount by the original price and multiplying by 100. For example: a $40 discount on $200 is (40 ÷ 200) × 100 = 20%.
How do I reverse a percentage?
To reverse a percentage (find the starting value before a percentage was applied), divide the final number by (1 ± percentage). Example: If 144 is after a 20% increase, the original value was 144 ÷ 1.20 = 120.
How do I calculate percentage difference?
Percentage difference measures how far apart two values are relative to their average. Use: ((|A − B|) ÷ ((A + B) ÷ 2)) × 100.
FAQ
What is a percentage?
A percentage is a way of expressing numbers as parts of 100. In percentage calculation, 1% represents one-hundredth of a whole. Percentages make it easy to compare values, measure increase or decrease, and understand proportions.
How do I calculate a percentage of a number?
To calculate the percentage of a number, multiply the base number by the percentage and divide by 100. Example: To find 30% of 200, do 200 × 0.30 = 60. This is one of the most common percentage calculations used for discounts, taxes, and statistics.
How do I calculate what percent one number is of another?
To find what percent one number is of another, divide the first number by the second number, then multiply by 100. Example: 25 is what percent of 80? → (25 ÷ 80) × 100 = 31.25%. This is useful for comparing values and analyzing data.
How do I calculate percentage increase or decrease?
Percentage increase or decrease compares the difference between two numbers relative to the original value. Use: ((new − old) ÷ old) × 100. Example: If a price rises from 50 to 70, the increase is ((70 − 50) ÷ 50) × 100 = 40%. This is widely used in finance, business, and growth analysis.
Why are percentage calculations important?
Percentage calculations help with budgeting, shopping discounts, profit margins, growth tracking, academic scores, statistics, and financial planning. Percentages simplify comparison and make numerical information easier to understand.
What is the easiest way to calculate percentages?
The fastest way is to use an online percentage calculator. It removes the need for manual formulas and instantly computes percent of a number, percent change, and percent comparisons with high accuracy.
What is the formula for percentage?
The general percentage formula is: (Part ÷ Whole) × 100. This formula applies to most percentage-related problems, including discounts, ratios, and data comparisons.
Can this calculator be used for discounts?
Yes. To calculate a discount, subtract the discount percentage from the original price. Example: A 20% discount on $150 is 150 × 0.20 = 30, so the final price is $120. This calculator can compute the discount amount or the final price.
How to Calculate Percentages (Complete Guide)
Use this free percentage calculator to find the percent of a number, calculate what percent one value is of another, and compute percentage increase or decrease. Below is a quick refresher with examples.
1) Percent of a number
Formula: (% × Base) ÷ 100. Example: 18% of 250 = 45. Try it in the percent of calculator.
2) What percent is A of B?
Formula: (A ÷ B) × 100. Example: 25 is what percent of 80? 31.25%. Use the what percent tool.
3) Percent increase/decrease
Formula: ((New − Old) ÷ Old) × 100. Example: from 50 to 70 = 40% increase. Try the percent change calculator.
Common pitfalls
- Dividing by zero when the whole (denominator) is 0.
- Confusing percentage points (absolute change) with percent change (relative change).
- For decreases, results are negative (e.g., −12%).
Use cases
Shopping discounts, tip calculation, profit margins, growth rates, exam scores, statistics, and financial analysis.
Free Percentage Calculators — Fast, Accurate, Private
Quick tools: percent of a number, what percent one number is of another, percent change, discount, tip, and percentage difference. All calculations run locally in your browser.