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What is X% of Y Calculator. Free Online

Free what is x% of y calculator. Instant results in your browser, e.g. 20% of 85 = 17. No signup.

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How it works

Pick a mode: percent of a value, what percent X is of Y, increase or decrease by a percent, or percent change between two values. Enter numbers in the sentence-style fields and read the result instantly.

About What is X% of Y Calculator. Free Online

Informational only, not professional advice. Report an error.

This page answers "what is X percent of Y?" without rearranging the formula. Multiply the percentage by the value and divide by 100.

Example: 20% of 85 = 17. Useful for discounts, tax estimates, tip math, and any problem where you know the rate and the whole.

Everything runs in your browser. Nothing you type is uploaded for the calculation.

Quick tips

  • Label which number is the base in what-percent problems, backwards inputs flip the answer.
  • Percent change is asymmetric, always report direction clearly in slides and reports.
  • For mental checks, 10% of a number is easy to halve for 5% or double for 20%.
  • Pair with the Unit Converter when a percentage applies to a measurement you still need to convert.

Formulas

  • percentOf: result = (a/100) × b
  • whatPercent: result = (a/b) × 100
  • increaseBy: result = a × (1 + b/100)
  • decreaseBy: result = a × (1 − b/100)
  • change: ((new − old) / |old|) × 100

Other percentage calculators

Open the full percentage calculator for every mode in one place.

This tool is part of the free General collection on FindMeTool. Explore more General tools or browse the full tool directory.

FAQ

How do I find X percent of a number?
Choose the percent-of mode, enter the percentage and the value, and read the result.
Can this calculate percent increase?
Yes. Use Increase by % on the hub, or open the Percentage Increase Calculator for a focused page.
Can this calculate percent decrease or change?
Yes. Use Decrease by % or % change on the hub, or open the dedicated long-tail pages linked below.
Is this percentage calculator free?
Yes, use it as often as you need.

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