Free online calculator

Percentage Calculator

Solve six common percentage calculations instantly, including increases, decreases, markups, and discounts.

Reviewed 17 August 2026 · Runs privately in your browser

Calculate your result

Find a percentage of a number.Formula :(X ÷ 100) × Y

Decimals and negative values are supported. Your entries never leave this page.

Six percentage calculations

  • X% of Y: (X ÷ 100) × Y
  • X as a percentage of Y: (X ÷ Y) × 100
  • Increase from X to Y: ((Y − X) ÷ |X|) × 100
  • Decrease from X to Y: ((X − Y) ÷ |X|) × 100
  • Add X% to Y: Y × (1 + X ÷ 100)
  • Subtract X% from Y: Y × (1 − X ÷ 100)

Worked example

20% of 150 is 30: 20 ÷ 100 × 150 = 30. Increasing 150 to 180 is a 20% increase; adding 20% to 150 also gives 180.

Frequently asked questions

How do I find X% of Y?

Divide X by 100, then multiply by Y.

Why can the denominator not be zero?

Ratios and changes divide by the whole or starting value. Division by zero is undefined.

Can I use decimals or percentages above 100?

Yes. All modes accept decimals, percentages above 100, and meaningful negative values.

What does a negative increase or decrease mean?

The values moved in the opposite direction from the selected mode.

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