Percentage Calculator

How It Works

1. 1

   Choose a calculation mode

   Select from three modes: 'X% of Y', 'X is what % of Y', or '% Change'.

2. 2

   Enter your values

   Input the numbers for your chosen mode. The result updates instantly.

3. 3

   Read the result and formula

   See the calculated answer with the formula shown for reference.

How Percentages Work

Percentages are one of the most frequently used mathematical concepts in everyday life, from calculating discounts and tax rates to understanding statistics and financial returns. The word 'percent' literally means 'per hundred' — so 25% means 25 out of every 100. Our calculator handles the three most common percentage operations: finding X% of a number (multiply the number by X/100), determining what percentage one number is of another (divide the part by the whole and multiply by 100), and calculating percentage change between two values ((new − old) ÷ old × 100). Percentage change is particularly important in finance and economics: a stock that rises from $80 to $100 has gained 25%, while one that falls from $100 to $80 has lost only 20% — illustrating why percentage changes are not symmetric. Our calculator provides instant results for all three modes, showing the formula used alongside the answer.

Frequently Asked Questions

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