Percentage Calculator

Calculation Mode

Percentage (%)

Of (Value)

Example: What is 20% of 200?

Part (X)

Whole (Y)

Example: 50 is what percent of 200?

Old Value

New Value

Example: Percentage change from 50 to 75?

⚡ All calculations are performed locally in your browser.

Result

Enter values and click "Calculate"

📦 Percentage Calculator Source Code $4.99

Get the complete, ready‑to‑deploy HTML file with all styling and logic. This is the exact code powering the demo above — no dependencies, works offline, and 100% client‑side. Supports three calculation modes: finding a percentage of a value, finding what percent one value is of another, and calculating percentage increase/decrease. Perfect for e‑commerce, finance, education, and everyday math. One‑time purchase, lifetime access.

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What Is a Percentage Calculator?

A percentage calculator is an essential math tool that solves three common types of percentage problems: finding a percentage of a number (e.g., 20% of 200), finding what percent one number is of another (e.g., 50 is what percent of 200), and calculating the percentage increase or decrease between two values (e.g., the percent change from 50 to 75). Percentages are used everywhere — from calculating discounts and sales tax to analyzing data trends and tracking financial growth. This tool handles all three scenarios with a clean, intuitive interface.

How to Use

Choose your calculation mode — "% of Value", "What %", or "% Change".
Enter the required values — the input fields change based on the selected mode.
Click "Calculate" — the result appears instantly in the right panel with a formula breakdown.
Copy the result with the Copy button, or clear everything with the Clear button.

Frequently Asked Questions

What is the formula for percentage change?

Percentage change = (New - Old) / Old × 100%. A positive result indicates an increase, while a negative result indicates a decrease.

Does this tool work offline?

Yes. Once the page loads, all calculations happen locally in your browser. No network requests are made.

What are the rounding rules?

The tool rounds results to 2 decimal places for percentages and 2 decimal places for numeric values, providing clear and readable outputs.

Disclaimer: This tool performs all operations locally in your browser. No data is stored, transmitted, or logged. Results are for informational purposes only.