Percentage Calculator - Percent Of, Percent Change, Increase & Decrease

What is X% of Y, X is what % of Y, percent increase, decrease, and change

🔒 100% in-browser🆓 Free forever⚡ No sign-up
Result
30
15% × 200 = 30
Estimates only. Results are generated by generalised formulas from the inputs you provide and are for informational purposes only. They are not financial, tax, legal, medical, or professional advice, and do not account for your individual circumstances, jurisdiction, taxes, fees, or health conditions. Verify important figures with a qualified professional. By using this tool you agree to our Terms & Disclaimer.

How it works

  1. 1
    Pick a mode

    Choose from: what is X% of Y, X is what % of Y, increase by %, decrease by %, or % change between two values.

  2. 2
    Enter two numbers

    Type the two values in the labeled fields. The result and formula update as you type.

  3. 3
    Read the formula

    Every answer shows the exact arithmetic used so you can double-check or teach it.

About Percentage Calculator - Percent Of, Percent Change, Increase & Decrease

Free online percentage calculator. Instantly compute what X% of Y is, what percent one number is of another, percentage increase, percentage decrease, and percent change between two values. Shows the formula used for every calculation. Runs entirely in your browser - no ads, no tracking, no sign-up. Percentage Calculator - Percent Of, Percent Change, Increase & Decrease on 712 Tools runs entirely inside your browser using modern JavaScript APIs - no server ever sees your data. That means instant results, complete privacy, and no upload limits.

Whether you need to what is x% of y, x is what % of y, percent increase, decrease, and change for a debugging session, a quick sanity check, or a production incident, this tool is free to use as many times as you need. There are no watermarks, no sign-up, and no ads inside the tool itself.

Frequently asked questions

How do I calculate X% of Y?

Multiply the two numbers and divide by 100. Example: 15% of 200 = (15 × 200) ÷ 100 = 30.

How do I find what percent X is of Y?

Divide X by Y and multiply by 100. Example: 30 is what percent of 200? (30 ÷ 200) × 100 = 15%.

What is percent change vs percent difference?

Percent change compares a new value to an original: ((new − old) ÷ old) × 100. Percent difference compares two values symmetrically.

Is my data sent anywhere?

No. All calculations run entirely in your browser.

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