Percentage Calculator

Calculate X% of Y, what percent X is of Y, and percent change. Everything runs in your browser.

X% of Y

Result: 30

X is what percent of Y

Result: 25%

Percent change

Result: 25%

Informational only; verify critical results independently.

How to use

  1. Choose a mode: “X% of Y”, “X is what percent of Y”, or “Percent change”.
  2. For X% of Y: enter the percent (e.g. 15) and the base number (e.g. 200). The result is 15% of 200.
  3. For what percent: enter the part (X) and the whole (Y). The result is the percentage that X is of Y.
  4. For percent change: enter the old value and the new value. The result is the percentage increase or decrease.
  5. Use a comma or period as the decimal separator; both are accepted.
  6. Results update as you type. No submit button required.
  7. Copy the result from the output if you need it elsewhere.

Examples

  • 15% of 200
    Input: X = 15%, Y = 200
    Output: 30
  • What percent is 30 of 120?
    Input: X = 30, Y = 120
    Output: 25%
  • Price increase from 100 to 125
    Input: Old = 100, New = 125
    Output: 25%
  • 20% of 1,500
    Input: X = 20%, Y = 1500
    Output: 300
  • What percent is 18 of 90?
    Input: X = 18, Y = 90
    Output: 20%
  • Salary cut from 60,000 to 57,000
    Input: Old = 60000, New = 57000
    Output: -5%
  • 8% of 240
    Input: X = 8%, Y = 240
    Output: 19.2
  • Tip: 18% of 45
    Input: X = 18%, Y = 45
    Output: 8.1

FAQ

How do I find X% of Y?
Multiply Y by X/100. Example: 15% of 200 = 200 × 0.15 = 30.
How do I find what percent X is of Y?
Divide X by Y and multiply by 100. Example: 30/120 = 0.25 → 25%.
How is percent change calculated?
((New − Old) / Old) × 100. Positive = increase, negative = decrease.
What’s the difference between percent and percentage points?
Going from 10% to 12% is +2 percentage points but a 20% relative increase.
Can I use decimals?
Yes. Enter 12.5 for 12.5%. Use a comma or period as the decimal separator.
Why does it show a dash (—)?
That means the inputs aren’t valid numbers or the base/whole is zero.
Is the result rounded?
The result is shown with standard number formatting; the underlying value is not rounded for further use.
Does it work for very large numbers?
Yes. JavaScript number limits apply, but normal everyday numbers are fine.
Where is my data sent?
Nowhere. All calculations run in your browser; nothing is sent to our servers.

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