How do I calculate X% of Y?

Multiply Y by X/100. Example: 15% of 200 = 200 × 0.15 = 30.

How do I find what percent A is of B?

Divide A by B, then multiply by 100. Example: 30 is what % of 200 = (30/200) × 100 = 15%.

How is percentage change calculated?

Percentage change = (New − Old) / Old × 100. Old value must not be 0.

How do I calculate a discount price?

Final price = Original × (1 − Discount/100). Savings = Original − Final.

Does this calculator send my numbers to a server?

No. All calculations run locally in your browser. Inputs are not uploaded.

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Percentage Calculator

Calculate percent of a number, reverse percent, percentage change, and discount price. Links are shareable and will restore your inputs automatically.

A) X% of Y

Example: 15% of 200 → 30

Rounding

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Currency (optional)

Percent (X)

Number (Y)

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Enter values to calculate.

How to use

Select a mode (A–D).
Enter numbers. Results update instantly.
Use Share or Copy share link to send a URL that restores inputs.

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What this means

This tool helps you translate everyday percentage math into clear numbers (discounts, growth rates, proportions).

Disclaimer: This calculator is for educational and informational purposes only and does not provide financial, tax, or legal advice. Rules, taxes, fees, rounding, and consumer protection requirements may differ by country and provider. Use at your own risk.
Privacy: All calculations run locally in your browser. No input data is sent to a server.

Related English tools

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Examples

A few common tasks this calculator covers

Percent of: 15% of 200 = 30
Reverse percent: 30 is what % of 200 = 15%
Change: 120 → 150 = +25%
Discount: 49.99 with 20% off = 39.99 (save 10.00)

FAQ

Quick answers to common questions

Why does the % change require Old value ≠ 0?

Percentage change divides by the old value: (New − Old) / Old × 100. Division by 0 is undefined.

Do you include taxes or fees in discounts?

No. This tool computes pure percentage math. Taxes, tips, and fees vary by country/provider and are not included.

Is my data uploaded?

No. Calculations run locally in your browser. The share link only stores numbers in the URL query.

Why do my results differ from other sites?

Differences usually come from rounding rules, whether taxes/fees are included, and how decimals are handled.