Percentage Calculator

Solve common percentage problems instantly

What is a Percentage Calculator?

A percentage calculator solves everyday percent problems: find X% of a number, find what percent one number is of another, or calculate percent increase and decrease. It saves time on homework, shopping discounts, business metrics, sales reporting, and quick mental-math checks.

Everything runs in your browser. You can experiment with different inputs to compare sale prices, growth rates, or test scores without spreadsheet setup or registration.

How to Use This Percentage Calculator

  1. Select the calculation mode available on the page (e.g., “X% of Y”, “X is what % of Y”, or change between values).
  2. Enter the values requested for that mode.
  3. View the result instantly; adjust inputs to compare scenarios.
  4. Switch modes to solve a different type of percent problem on the same page.

Common Formulas

X% of Y: result = (X ÷ 100) × Y. What percent: (part ÷ whole) × 100. Percent change: ((new − old) ÷ old) × 100. Reverse: if you know the final price after a discount, original = final ÷ (1 − discount% ÷ 100).

Results are informational; verify financial or tax calculations with official sources when money is involved. Rounding on receipts may differ slightly from theoretical percentages used in spreadsheets or billing systems.

Frequently Asked Questions

How do I find 20% of a number?

Multiply the number by 0.20, or divide by 5. Example: 20% of 150 = 30. Use the “percent of” mode and enter 20 and 150 for the same result.

How do I calculate percent increase?

Subtract the original from the new value, divide by the original, and multiply by 100. Example: from 80 to 100 is a 25% increase. Select the increase/decrease mode if available on the tool.

Can I use this for tips or tax?

Yes for quick estimates. For splitting bills with tip and tax together, our dedicated Tip Calculator may be more convenient.

Does it handle decimals?

Yes. Enter decimal values where needed; the calculator uses floating-point arithmetic appropriate for everyday use.

How do I calculate a 15% discount?

Find 15% of the original price and subtract it, or multiply the price by 0.85. Example: $80 with 15% off → save $12, pay $68. Use the percent-of mode with 15 and 80 to get the discount amount quickly.

Related Tools

Explore Tip Calculator, Loan Calculator, and Fraction Calculator for restaurant bills, loan estimates, and rational number math.