Answerivo

Everyday Math

Percentage Calculator

Most percentage questions are one of three shapes, and mixing them up is what makes the answer feel wrong. Choose the question you are actually asking, enter two numbers, and get the answer with the arithmetic written out.

Step 1

Enter your numbers

The percentage in the first question, otherwise the first number.

The second number.

Results update as you type. Nothing you enter leaves your device.

Step 2

Results

Fill in the form and your results appear here instantly.

Estimates only. Verify important figures against your own records before acting on them. See our disclaimer.

What this calculator includes

What you enter

  • Which question?
  • X
  • Y

What you get back

  • Percentage increase
  • Absolute change
  • Y as a percent of X

How this calculation works

How this calculation works

All three questions come from the same relationship between a part, a whole, and a rate. Naming which one you are solving for is most of the work.

  • X% of Y = X ÷ 100 × Y
  • X is what percent of Y = X ÷ Y × 100
  • Percentage change from X to Y = (Y − X) ÷ |X| × 100
  • Percentage change is positive for an increase and negative for a decrease

What the result means

Each mode answers a different question. "Percent of" scales a number, "is what percent of" turns two numbers into a share, and percentage change measures movement from a starting value — positive for an increase, negative for a decrease.

Common mistakes and assumptions

  • Reversing the two numbers in a percentage change. The first value is the baseline you divide by.
  • Expecting a drop and a rise of the same percentage to cancel out — they do not, because the base changes.
  • Using percentage change when you want percentage points; a rate moving from 4% to 5% is a one-point rise and a 25% change.

Worked example

A price moved from $180 to $216 and you want the percentage change.

  1. 1Absolute change = $216 − $180 = $36.
  2. 2Percentage change = $36 ÷ $180 × 100 = 20% — an increase.
  3. 3Note that going back from $216 to $180 is a 16.67% decrease, not 20%: the base changed.
  4. 4Switch to "X is what percent of Y" with 36 and 180 to confirm the same 20%.
  5. 5Switch to "What is X% of Y" with 20 and 180 to get the $36 back.

Frequently asked questions

Why isn't a 20% increase reversed by a 20% decrease?
Because the base changes. Going up 20% from 100 gives 120; taking 20% off 120 gives 96. To undo a 20% increase you need a 16.67% decrease.
Can I use negative numbers?
Yes. Percentage change uses the absolute value of the starting number so the sign of the result still reads correctly as an increase or a decrease.
What is a percentage point?
A percentage point is a plain difference between two percentages. Going from 4% to 6% is a rise of 2 percentage points, but a 50% increase.
How do I take a percentage off a price?
Use the first mode and read the "Y decreased by X%" line, or use the discount calculator, which also shows what you save.

Disclaimer

This calculator returns estimates based only on the values you enter. It does not account for taxes, financing terms, local regulations, or conditions specific to your operation, and it is not accounting, legal, tax, or investment advice. Confirm any figure that carries real cost before you rely on it.

Calculations run entirely in your browser and the numbers you type are never sent to us or stored. Read how Answerivo calculators are built.

Formulas and worked example last reviewed .