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What is X% of Y?
What is % of ?
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X is what % of Y?
is what % of ?
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Percentage increase / decrease
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How to use the percentage calculator

This free tool offers three calculation modes. Simply enter your values and the result appears instantly — no need to press any button.

Mode 1: What is X% of a number?

Enter the percentage and the base number. Example: What is 15% of 80? Answer: 12.

Mode 2: X is what percentage of Y?

Enter both numbers. Example: 25 is what % of 200? Answer: 12.5%.

Mode 3: Percentage increase or decrease

Enter a base value and a percentage, then choose whether to increase or decrease. Example: 100 increased by 20% = 120.

FAQ — Percentage Calculator

How do I calculate a percentage without a calculator?

The basic formula is: result = (percentage ÷ 100) × number. For example, 20% of 50 = (20 ÷ 100) × 50 = 10.

How do I calculate a percentage increase?

Percentage increase = ((new value − old value) ÷ old value) × 100. Example: from 80 to 100 = ((100−80) ÷ 80) × 100 = 25%.