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Percentage Calculator online

Calculate percentages, percentage change, increase, and decrease

Percentage Calculator logo
by
CHUNKY
MUNSTER
// What is X% of Y?
% of = 30
// X is what % of Y?
is what % of = 15%
// Percentage change from X to Y
From to = +25%

Percent Solver Instructions

  1. Enter the values into the respective rows for the calculation you need.
  2. Observe the results update instantly as you type.
  3. Use the different modes for basic percentages, reverse percentages, or changes.
  4. Copy the result for your spreadsheet or documentation.

Percentage Calculator provides the fastest way to solve common math problems like "what is X percent of Y", "X is what percent of Y", and "percentage change from X to Y". Each row in this math tool recalculates instantly, accepts decimals and negatives, and strips trailing zeros so you get "30" instead of "30.0000".

Percentage Difference Logic

Percentage change is computed as (new − old) divided by the absolute value of the old number, then multiplied by 100. Using |old| matters when the baseline is negative - without it, a recovery from −50 to −20 would report the wrong sign. The result is signed so a rise reads as "+25%" and a fall as "−20%", which is the asymmetry many shoppers and investors get wrong.

Frequently Asked Questions

How is "percentage change" different from "percentage difference"?

Percentage change uses the original value as the denominator: (new − old) / |old| × 100. Percentage difference uses the average of the two values and is symmetric. This tool computes change, which is the right choice when one number is a clear "before" and the other an "after".

Why does the change show "+" or "−"?

A signed result distinguishes growth from shrinkage. Going from 100 to 125 is +25%; going from 125 to 100 is −20%. The two are not symmetric - that asymmetry trips up people who assume a 25% rise can be cancelled by a 25% fall.

Can I enter negative numbers?

Yes. The "From X to Y" mode divides by the absolute value of the starting number, so changes from negative baselines (for example, a loss shrinking from −50 to −20) report sensibly.

Why does the result show four decimals sometimes?

Outputs are computed to four decimal places and then trailing zeros are stripped. A clean result like 30 stays as "30"; a recurring decimal like 1/3 of 100 shows as 33.3333.

Explore the full suite of Number tools and 290+ other free utilities at Chunky Munster. For fast financial or statistical calculations, bookmark this Percentage Calculator.

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