# Percentage Calculator — Free Online

Work out percentages: X% of Y, what percent X is of Y, and percentage change. 100% in your browser — free, no sign-up.

## What can it calculate?

Three of the most common percentage questions: what is X% of Y, X is what percent of Y, and the percentage change from one number to another. Pick the mode and enter two numbers.

## How it works

All three formulas run in your browser as you type, so you get the answer instantly with no rounding surprises. Nothing is sent anywhere.

## When to use it

Calculate a discount or tip, work out a tax or markup, find a test score as a percentage, compare two figures, or measure growth and decline between two values.

## Percentage change explained

Percentage change is the difference between two values relative to the first: (new − old) ÷ old × 100. A positive result is an increase, a negative one is a decrease — useful for prices, metrics, and results over time.

## How to

1. Choose the calculation type.
2. Enter the two numbers.
3. Read the result instantly.

## FAQ

**What calculations does it support?**

Three: what is X% of Y, X is what percent of Y, and the percentage change from one number to another.

**How is percentage change calculated?**

As (new − old) ÷ old × 100. A positive result is an increase, a negative one a decrease.

**Is my data sent anywhere?**

No. Everything is computed in your browser as you type.

**Can I use it for discounts and tips?**

Yes. Use "X% of Y" for a discount or tip amount, and percentage change to compare prices.

**Is it free?**

Yes, completely free — no sign-up and no watermark.

**Is my data private?**

Yes — this tool runs entirely in your browser. Your files and text are never uploaded.


## Related

- [Loan & Mortgage Calculator — Free](/calc/loan-calculator)
- [BMI Calculator — Free, Metric & Imperial](/calc/bmi-calculator)
- [Age Calculator — Free, Exact Age](/calc/age-calculator)