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Percentage Calculator

Calculate percentages quickly: increase, discount, ratio and percentage change. 4 calculation modes with instant results. Free online calculator.

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Percentage Calculator Online

Use our free percentage calculator to solve the three most common percentage problems instantly. Choose one of three modes and get your answer in real-time as you type — no need to click any button or wait for results.

Mode 1 — What is X% of Y? Enter a percentage and a base value to find the result. For example, 15% of 200 equals 30. This is useful for calculating discounts, tips, tax amounts, markups, and commissions. The formula applied is: result = Y × (X ÷ 100).

Mode 2 — X is what percent of Y? Enter two numbers to find what percentage the first represents of the second. For example, 30 is 15% of 200. This mode is perfect for grade calculations, budget analysis, progress tracking, and market share computations. The formula applied is: percentage = (X ÷ Y) × 100.

Mode 3 — Percentage Variation from X to Y. Enter an original value and a new value to calculate the percentage change between them. A positive result indicates an increase, while a negative result indicates a decrease. For instance, a price change from 80 to 100 represents a 25% increase, while a change from 100 to 80 is a 20% decrease. The formula applied is: variation = ((Y − X) ÷ X) × 100. This is essential for analyzing price changes, salary adjustments, stock performance, and growth metrics.

The tool displays the formula used alongside every result, helping students and professionals understand the mathematical reasoning. It handles decimals, negative numbers, and very large values with full precision.

All calculations are performed 100% in your browser — no data is sent to any server, ensuring complete privacy. For other useful tools, try our BMI Calculator or Character Counter.

Frequently Asked Questions

How do I calculate percentage of a value?
To find X% of Y, multiply Y by X and divide by 100. For example: 15% of 200 = 200 × 15 ÷ 100 = 30.
How do I calculate percentage variation?
Use the formula: ((new value − old value) ÷ old value) × 100. A positive result means increase, negative means decrease.
What is the difference between discount and markup?
The calculation base is different. A 20% discount on R$100 gives R$80. But a 20% markup on R$80 gives R$96, not R$100. To go back to the original value, you need a 25% markup. This is a common mistake in pricing. Use our Hours Calculator if you need to calculate hourly rates.