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Percentage Calculator

Solve common percentage questions in one flexible calculator.

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Inputs

Results

Result Enter values to calculate.
Your result explanation will appear here.

Useful next checks

  • Use the result to check your working or homework.
  • Change one input at a time to see how the answer moves.
  • Read the method below if you want the steps.

Intro

Use this percentage calculator to answer common percentage questions, including percentage of a number, one number as a percentage of another, and percentage change between two values.

What this percentage calculator does

Choose the mode that matches your question, then enter the values. The calculator can help with shopping, schoolwork, finance checks, statistics, and everyday comparisons.

Common uses include:

  • Find 20% of 150.
  • Find what percentage 20 is of 150.
  • Find the percentage increase or decrease from one value to another.
  • Check discount, tax, tip, or growth calculations.

How it works

The formula depends on the mode. For "what percentage is this part of the whole", the formula is part / whole x 100.

For "percentage of a number", the calculator converts the percentage to a decimal and multiplies it by the number. For percentage change, it compares the difference with the original value.

Example calculation

20% of 150 is 30 because 20% is 0.20 and 150 x 0.20 = 30.

If 20 is compared with 150, then 20 / 150 x 100 = 13.33%, so 20 is about 13.33% of 150.

How to use the result

Check that the mode matches the wording of your question. "20% of 150" and "20 as a percentage of 150" are different questions, so they produce different results.

For sale prices, use the Discount Calculator. For before-and-after changes, use the Percentage Increase Calculator.

Assumptions and limitations

  • A denominator or original value of zero may make some percentage questions undefined.
  • Percentage change can be positive, negative, or zero.
  • Rounding may cause small differences from manual calculations.
  • The calculator does not decide which percentage question you mean; choose the mode carefully.

FAQs

  • What is the easiest percentage formula? For part of a whole, use part divided by whole, then multiply by 100.
  • Why is percentage change from zero undefined? Because percentage change divides by the original value, and division by zero is not valid.
  • Can percentages be over 100%? Yes. A value can be more than 100% of another value, and an increase can exceed 100%.
  • Is a percentage point the same as a percent? No. Moving from 5% to 6% is a 1 percentage point increase, but a 20% relative increase.

Related calculators

Frequently asked questions

Can I calculate percentage change?

Yes. Choose the percentage change mode and enter the old and new values.

Why do some results need a non-zero value?

Division by zero is undefined, so some percentage calculations cannot use zero as the denominator.

MathHow to Calculate Percentage IncreaseA simple guide to percentage increase, from bills and prices to business metrics, with the baseline mistake explained clearly.FinanceHow to Calculate a DiscountA shopper-friendly guide to sale prices, percentage-off offers, stacked discounts, and the difference between savings and final price.BusinessHow to Calculate Profit MarginA small-business guide to gross profit margin, markup, pricing checks, and why discounts can quietly squeeze profitability.StatisticsHow to Calculate Standard DeviationA readable introduction to standard deviation, variation, and why the average alone rarely tells the whole story in a dataset.