Percentage Calculator

Six percentage calculators in one: X% of Y, X is what percent of Y, percent change, increase or decrease by a percent, and percent difference.

What is % of ?
is what % of ?
% change from to ?
Increase by %
Decrease by %
% difference between and

Percentage formulas

  • X% of Y = X ÷ 100 × Y. 15% of 200 = 30.
  • X is what % of Y = X ÷ Y × 100. 30 is 25% of 120.
  • Percent change = (new − old) ÷ |old| × 100. From 80 to 100 is +25%.
  • Increase by % = X × (1 + P/100). Decrease by % = X × (1 − P/100).
  • Percent difference = |A − B| ÷ ((A + B) ÷ 2) × 100, used when neither value is the “original”.

A common trap

A 20% drop followed by a 20% rise doesn't get you back where you started: 100 → 80 → 96. Percent changes compound; they don't add.

Percentage points vs. percent

If a conversion rate moves from 4% to 5%, that's a rise of 1 percentage point but a 25% increase.

Related tools

Hourly to Salary Calculator

Convert hourly wage to annual salary and back, plus weekly, biweekly, semi-monthly and monthly pay. Adjustable hours per week and paid weeks.

Meeting Cost Calculator

Calculate the cost of a meeting from attendees, salaries and length—per meeting and per year for recurring meetings. Include benefits overhead.

FAQ

Is Percentage Calculator safe for confidential files?

Yes. It runs entirely inside your browser, so your files and text are never uploaded to a server.

Is Percentage Calculator free?

Yes — free with no sign-up, no daily limits and no watermark.

Does it work on my phone?

Yes. FileMoss tools work in current iPhone and Android browsers as well as on desktop.