Percentage Calculator
Calculate any percentage in one click. Simple, fast, and accurate — no sign-up needed.
How to Calculate Percentages
A percentage represents a fraction of 100. The word itself comes from the Latin per centum, meaning "by the hundred." Percentages are everywhere in daily life — from discounts and tips to interest rates and statistics. This calculator covers the five most common percentage operations you'll encounter.
Finding a Percentage of a Number
This is the most common operation. You want to know what a certain percent of a given number is. The formula is straightforward:
(15 ÷ 100) × 300 = 0.15 × 300 = 45
Use this when calculating tips at restaurants, sale prices, tax amounts, or any situation where you need a portion of a total.
Finding What Percent One Number Is of Another
When you know the part and the whole, this formula gives you the percentage:
(42 ÷ 168) × 100 = 25%
Useful for grades, test scores, conversion rates, and understanding proportions in data sets.
Percentage Change
Percentage change tells you how much a value has increased or decreased relative to its original amount:
((100 − 80) ÷ 80) × 100 = +25%
Commonly used in finance, business reporting, and tracking growth metrics over time.
Percentage Increase & Decrease
When you want to apply a percentage increase or decrease to a value, the formulas are:
Decrease: Value × (1 − Percentage ÷ 100)
Decrease $200 by 15%: 200 × 0.85 = $170
Percentage Difference
Unlike percentage change, percentage difference compares two values without assigning direction. It uses the average of both values as the denominator:
(|40 − 60| ÷ ((40 + 60) ÷ 2)) × 100 = (20 ÷ 50) × 100 = 40%
Useful when comparing two independent measurements, such as prices from different vendors or performance metrics between two periods.
Frequently Asked Questions
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Multiply the number by the percentage and divide by 100. For example, 25% of 200 = (200 × 25) / 100 = 50. You can also convert the percentage to a decimal first: 25% = 0.25, then 0.25 × 200 = 50.
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Percentage increase = ((New Value − Old Value) / Old Value) × 100. For example, if a price goes from $80 to $100, the increase is ((100 − 80) / 80) × 100 = 25%.
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Percentage change = ((New Value − Old Value) / |Old Value|) × 100. A positive result means an increase, a negative result means a decrease. This works for any directional change — prices, quantities, scores, and more.
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Percentage change measures the change from one specific value to another (it has a direction), while percentage difference compares two values symmetrically without implying which came first. Percentage difference uses the average of both values as the denominator.
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Divide the part by the whole and multiply by 100. For example: 30 is what percent of 150? Answer: (30 / 150) × 100 = 20%.
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Yes. This calculator works for any percentage operation — tips, taxes, discounts, profit margins, investment returns, salary increases, and more. All calculations run locally in your browser with full decimal precision.