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Percentage Calculator — % of, % change, ratio

Three-in-one percentage calculator: X% of Y, X as a % of Y, and % increase/decrease. Instant, client-side.

Free No signup Client-side Privacy friendly Updated

What is X% of Y?

X is what % of Y?

% change from X to Y

How to use

  1. 1 Pick the calculation you need — three common percentage problems are shown.
  2. 2 Type your numbers; the answer updates instantly.
  3. 3 No rounding surprises — results show up to 6 significant digits.

Why use this tool

  • Three calculators in one: percent of a number, ratio as a percent, and percent change.
  • Instant, no signup, runs entirely in your browser.
  • Handles decimals and negatives.

Frequently asked questions

How do I find X% of Y?

Multiply: (X ÷ 100) × Y. For example, 15% of 200 = 0.15 × 200 = 30.

How do I work out what percent X is of Y?

Divide and multiply by 100: (X ÷ Y) × 100. For example, 30 of 200 = (30 ÷ 200) × 100 = 15%.

How is percentage change calculated?

((new − old) ÷ |old|) × 100. A result with a minus sign is a decrease.

Is my data sent anywhere?

No. Everything runs locally in your browser — nothing is uploaded.

What is Percentage Calculator?

A percentage calculator computes the three most common percentage problems: a percentage of a number, one number as a percentage of another, and the percentage change between two numbers.

Features

Three percentage modes

"X% of Y", "X is what % of Y", and "% change from X to Y" — all on one screen.

Live results

Answers update instantly as you edit any field.

Free & private

Runs on your device — no signup, nothing uploaded.

Example

Input

What is 15% of 200?

Output

30

Common use cases

  1. 1

    Discounts & tips

    Work out a sale price or a tip as a percentage of the total.

  2. 2

    Grades & scores

    Find what percent a score is of the maximum.

  3. 3

    Growth & change

    Compute the percent increase or decrease between two values.

Summary

Zerethon's percentage calculator solves the three common percentage questions in your browser: what is X% of Y, X is what percent of Y, and the percent change from X to Y. Each is computed live as you type. Everything runs client-side — nothing is uploaded.

Category
Math
Pricing
Free
Privacy
Browser-based
Signup
Not required

References

Privacy

Your data never leaves your browser unless explicitly stated. Percentage Calculator runs entirely client-side — no server upload, no logging, no tracking of your input.

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