How do I calculate a percentage of a number?

Multiply the number by the percentage, then divide by 100. For example, 20% of 150 is (20 ÷ 100) × 150 = 30.

How is percentage increase calculated?

Percentage change = ((new − original) ÷ |original|) × 100. If a price goes from $80 to $100, the increase is 25%.

How do I calculate a tip?

Multiply the bill by the tip percentage divided by 100. An 18% tip on $64.50 is $11.61, for a total of $76.11.

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Percentage Calculator

Calculate any percentage in seconds — percent of a number, increase & decrease, tips, and discounts. Clean, fast, and built for mobile.

What is X% of Y?

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How to use this percentage calculator

PercentBox is a free online percentage calculator designed for speed and clarity. Pick a mode, type your numbers, and get results instantly — no submit button needed. Perfect for schoolwork, shopping discounts, restaurant tips, markups, and everyday math.

What is X% of Y?

Find any percentage of a number. Example: What is 15% of 200? Answer: 30.

X is what % of Y?

Discover the relative size of two numbers. Example: 40 is 20% of 200.

Increase / Decrease

Raise or lower a value by a percent. Example: 100 increased by 12% = 112.

Percentage Change

Measure growth or decline from A to B. From 50 to 75 is a 50% increase.

Common percentage formulas

Goal	Formula
X% of Y	(X ÷ 100) × Y
X is what % of Y	(X ÷ Y) × 100
% increase / decrease	((new − old) ÷ \|old\|) × 100
Value after % change	value × (1 ± percent/100)

Frequently asked questions

How do I calculate a percentage of a number?: Multiply the number by the percentage, then divide by 100. For example, 20% of 150 is (20 ÷ 100) × 150 = 30. Use the “What is X% of Y?” tab above for instant results.
How do I find what percent one number is of another?: Divide the first number by the second, then multiply by 100. Example: 25 is what percent of 200? (25 ÷ 200) × 100 = 12.5%.
How is percentage increase calculated?: Percentage change = ((new − original) ÷ |original|) × 100. If a price goes from $80 to $100, the increase is ((100 − 80) ÷ 80) × 100 = 25%.
How do I calculate a tip?: Multiply the bill by the tip percentage divided by 100. An 18% tip on $64.50 is 0.18 × 64.50 = $11.61, for a total of $76.11. Our tip calculator can also split the bill.
How do I calculate a discount?: Savings = original price × (discount % ÷ 100). Final price = original − savings. A 25% off $79.99 item costs $59.99 and saves you $20.00.