onlinecalculator.me

Free online percentage calculator

A percentage is a number out of 100 — so 25% means 25 out of 100. This calculator handles the five most common percentage questions in one place.

What do you want to calculate?
Result
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About this calculator

How to use

  1. Pick the mode that matches your question using the radio buttons at the top.
  2. Enter the two values — X and Y. The labels tell you what each one represents.
  3. The result updates as you type.
  4. Use “Share with my numbers” to send the specific calculation to someone else.

The five modes

ModeFormulaExample
What is X% of Y?Y × X / 10015% of 200 = 30
X is what % of Y?(X / Y) × 10030 of 200 = 15%
% change from X to Y(Y − X) /X
Increase Y by X%Y × (1 + X/100)200 + 15% = 230
Decrease Y by X%Y × (1 − X/100)200 − 15% = 170

Worked examples

Tip on a restaurant bill: 18% of $54.50 → use mode 1 → $9.81

Sale discount: An item originally $80 is now $60. What’s the discount? → 60 is what % of 80? → 75%, so a 25% discount.

Salary raise: You earn $65,000 and get a 4.5% raise. Increase $65,000 by 4.5% → $67,925.

Stock drop: A stock fell from $120 to $90. Percent change → (90 − 120) / 120 × 100 = −25%.

Notes

  • Division by zero (Y = 0 in the “what percent” and “percent change” modes) returns a dash rather than crashing.
  • Results are rounded to 6 decimal places for display.

Frequently asked

How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100. Example: 15% of 200 = 200 × 0.15 = 30. Select the 'What is X% of Y?' mode.
How do I find what percent one number is of another?
Divide the first number by the second, then multiply by 100. Example: 30 is what percent of 200? (30 / 200) × 100 = 15%. Select the 'X is what percent of Y?' mode.
How is percent change calculated?
Percent change = ((New − Original) / |Original|) × 100. A positive result means an increase; negative means a decrease. Example: from 80 to 100 is a 25% increase.
How do I increase a number by a percentage?
Multiply the number by (1 + percentage/100). Example: increase 200 by 15% → 200 × 1.15 = 230. The calculator does this automatically in 'Increase Y by X%' mode.
How do I decrease a number by a percentage?
Multiply the number by (1 − percentage/100). Example: decrease 200 by 15% → 200 × 0.85 = 170. Use 'Decrease Y by X%' mode.