Percentage CalculatorYTScript

Percentage Increase Calculator

See how much a number rose, or what you get after increasing a value by a percent.

Runs in your browser — numbers never leave this device

Enter two numbers

Pick a question and fill both fields — the answer appears as you type.

How to use it

  1. 1

    Choose “from one number to another” or “increase a number by a percent.”

  2. 2

    Enter the values. The result appears as you type, in words as an increase or a decrease.

  3. 3

    Read the comparison if you actually wanted a directionless difference, and follow the link to that page.

Increase is not the same as a difference

A decrease and a difference are different formulas — those results are shown alongside for the same numbers.

A percentage increase (or decrease) takes the starting value as the base: (new − old) / |old| × 100. From 100 to 200 is an increase of 100%. From 200 back to 100 is a decrease of 50%, because the starting point changed. The denominator uses the absolute value of the start so a move from −50 to −40 is reported as an increase of 20%, not a confusing signed fraction.

A percentage difference ignores direction and compares both values to their average. For 100 and 200 that difference is 66.67%, which is neither 100% nor 50%. If you started at zero, a percentage change is not defined — there is no base to divide by.

Other percentage tools

Percentage calculatorFind a percent of a number, or what percent one number is of another.Percentage decreaseHow much a number fell, or reduce a value by a percent.Percentage differenceHow far two numbers sit from their average.DiscountSale price, amount saved, or the original price.TipTip amount, total to pay, and an optional split.Test scoreTurn points scored and a total into a percentage.FractionConvert fractions, decimals, and percentages.

Frequently asked questions

What is the formula for a percentage increase?

Subtract the old value from the new one, divide by the absolute value of the old value, and multiply by 100. A positive result is an increase; a negative result is a decrease.

Why is 100 to 200 a 100% increase, but 200 to 100 only a 50% decrease?

Each calculation uses its own starting point as the base. Doubling 100 adds a full 100, which is 100% of the start. Cutting 200 in half removes 100, which is only 50% of 200.

Can I increase a number by a percent instead?

Yes. Choose the second option and enter the starting value and the percent. The new amount is the starting value times (1 + P/100). A 10% increase on 500 is 550.

What if the starting value is zero?

A percentage change from zero is not defined. The page tells you that in plain language instead of showing Infinity.

Is this the same as a percentage difference?

No. Difference uses the average of the two numbers as the base and does not care which one came first. This page always shows that other figure next to the change, with a link.