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Percentage Calculator

Free online percentage calculator with four modes: percent of a number, X is what percent of Y, percent change, and tip / split.

  • Runs in browser
  • No signup
  • No tracking
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How to use Percentage Calculator

  1. Pick the mode that matches your question.

  2. Type the numbers — results update on every keystroke.

  3. Copy the answer with one click.

When to use it

  • Calculating discount prices and sale markdowns.

  • Quick tax / tip math at a restaurant.

  • Reporting growth or churn percentages.

  • Splitting bills across friends.

What it fixes

  • Forgetting whether percent change uses old or new as the denominator.

  • Hand calculation errors that get embarrassing in front of clients.

  • Floating-point output cluttering the result.

About Percentage Calculator

Percentages are everywhere — markups, discounts, growth rates, taxes, tips. This calculator handles the four most common questions in dedicated modes so you don't have to remember the formulas:

1. What is X% of Y? 2. X is what % of Y? 3. Percent change from X to Y. 4. Tip + split a bill across N people.

All four run live as you type. No ads, no tracking, no signup.

References: Wikipedia — Percentage · Wikipedia — Percent change

Frequently asked

  • How is percent change calculated?

    ((new − old) / |old|) × 100. Negative result = decrease. If the old value is zero, percent change is undefined.

  • Why round differences?

    Floating-point arithmetic can produce values like 0.30000000000000004. The tool rounds to a sensible precision but stores the full value internally.

  • Are calculations private?

    Yes. Everything runs locally in your browser — no values are sent anywhere.

Discussion

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