Z

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.

Summary

Percentage Calculator is a free math utility by Zerethon Tools. Three-in-one percentage calculator: X% of Y, X as a % of Y, and % increase/decrease. Instant, client-side. Runs entirely in the browser — no signup, no upload.

Category
Math
Pricing
Free
Privacy
Browser-based
Signup
Not required

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.

Related tools

Scientific Calculator

Online scientific calculator — trig, log, powers, roots, factorial, π/e, DEG/RAD, with a proper expression parser. Client-side.

Open tool

Fraction Calculator

Add, subtract, multiply and divide fractions with automatic simplification, decimal and mixed-number output. Client-side.

Open tool

Combinations & Permutations Calculator

Exact nCr, nPr and n! with big-integer precision. Client-side, no signup.

Open tool

Roman Numeral Converter

Two-way Roman numeral converter (1–3999) with full validation. Client-side.

Open tool

Build, share, and grow on Zerethon Social

Free signup. Earn points, collect achievements, and connect with creators worldwide.

Sign up free