Skip to content
FreeToolsDaily

Percentage calculator

Six everyday percentage calculations in one place, with the formula shown for every answer.

Free No sign-up Runs in your browser

How it works

How to use the Percentage Calculator tool

  1. 1

    Pick the calculation

    Each card answers a different percentage question, such as “What is 15% of 200?”.

  2. 2

    Type your numbers

    Results update instantly as you type.

  3. 3

    Copy the answer

    Use the copy button, and check the formula shown under each result.

The formulas

X% of Y = X ÷ 100 × Y. X as a percent of Y = X ÷ Y × 100. Percentage change from A to B = (B − A) ÷ |A| × 100. Increasing A by X% = A × (1 + X ÷ 100); decreasing = A × (1 − X ÷ 100). If X is P% of a number, that number is X ÷ P × 100.

Everyday examples

Shopping: a 25% discount on 1,200 saves 300, so you pay 900. Salaries: going from 50,000 to 56,000 is a 12% raise. Exams: 42 out of 60 is 70%. Prices: adding 18% tax to 1,000 gives 1,180.

Note that percentage changes aren't symmetric. A 20% fall followed by a 20% rise leaves you 4% below where you started.

Limitations

We’d rather be upfront about what this tool can’t do yet:

  • Results are rounded to at most six decimal places for display.

FAQ

Frequently asked questions

How do I calculate a percentage increase?

Use “Percentage change”: enter the old value first and the new value second. A positive result is an increase, a negative one a decrease.

How do I work out a discount?

Use “Decrease by %”: enter the price and the discount percentage to get the final price.

Why does percentage change say undefined for zero?

Change from zero can't be expressed as a percentage, because it involves dividing by zero.

Keep going

Related tools

All calculators