Percentage Calculator

X% of Y = (X/100) × Y · % change = ((Y−X)/X) × 100

Ratio & Percent

How to Use This Tool

Four Percentage Calculators in One

This tool handles the four most common percentage calculations:

  1. What is X% of Y? — Find a percentage of a value. Example: 15% of 200 = 30.
  2. X is what % of Y? — Find what percentage one value is of another. Example: 30 is 15% of 200.
  3. % change from X to Y — Calculate the percent increase or decrease. Example: from 100 to 125 is +25%.
  4. Discount (% off) — Calculate the final price after a discount. Example: $50 with 20% off = $40.

Percentage Formulas

Calculation Formula
X% of Y (X / 100) × Y
X is what % of Y (X / Y) × 100
% change from X to Y ((Y − X) / X) × 100
Y after X% off Y × (1 − X/100)

Formula & Explanation

Percentages are ratios expressed as a fraction of 100. The word 'percent' comes from Latin 'per centum', meaning 'by the hundred'.

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Frequently Asked Questions

How do I calculate 15% of 200?

Multiply 200 by 0.15 (or by 15/100): 200 u00d7 0.15 = 30. So 15% of 200 is 30.

How do I calculate percent change?

Subtract the original from the new value, divide by the original, multiply by 100. Example: from 80 to 100 u2192 (100-80)/80 u00d7 100 = 25% increase.

How do I calculate a discount?

Multiply the price by (1 - discount%/100). Example: $80 with 25% off u2192 80 u00d7 (1 - 0.25) = 80 u00d7 0.75 = $60.

What's the difference between percent increase and percent change?

They're the same calculation. Positive percent change is an increase; negative is a decrease. 'Percent increase' usually implies the result is positive.