Percentage Change Calculator

Calculate percentage increase or decrease between two values.

By Konstantin Iakovlev · Updated September 2026 · Source: Khan Academy

Percentage Change

25.00%

Direction

Increase

Calculation

Old Value200.00
New Value250.00
Difference50.00
Percentage Change25.00%

Use the Percentage Change Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only. Results are estimates based on the information you provide and the assumptions described on this page.

How It Works

Percentage change captures the size of an increase or decrease between two numbers, scaled against the starting point. That makes it a workhorse for tracking growth or decline in everything from household budgets to company results.

The method subtracts the initial value from the final value, divides that difference by the initial value, and multiplies by 100 to render the result as a percentage. In formula form: ((Final Value - Initial Value) / Initial Value) * 100%. A positive outcome marks an increase, and a negative one marks a decrease. If the initial value is negative, the calculator divides by its absolute value so the sign still shows the direction: going from -50 to -25 is a 50% increase.

Pin down which number is the Initial Value and which is the Final Value before you start, because swapping them inverts the answer. A drop should land as a negative percentage, which is the figure honestly reflecting the decline. Watch for an initial value of zero as well, since dividing by zero leaves the result undefined.

Example: Six Months of Stock Growth

  1. 1 Initial Value: a share bought at $150.
  2. 2 Final Value: six months later the same share trades at $180. Calculation: (($180 - $150) / $150) * 100 = (30 / 150) * 100 = 0.2 * 100 = 20%.
  3. 3 Result: the calculator shows a Percentage Change of 20.00%, Direction: Increase, and a Difference of 30.00.
  4. 4 Context: a 20% gain over six months is not a 20% annual return; two such half-years in a row would compound to 44% (1.2 × 1.2 = 1.44). The move back is not symmetric either: a fall from $180 to $150 is a 16.67% decrease.

Source: Khan Academy · Last updated: September 2026

Frequently Asked Questions

What is the formula for calculating percent increase or decrease?
Percentage change equals (new value minus old value) divided by the old value, times 100. A positive result is an increase and negative is a decrease. For example, going from 50 to 75 is a 50% increase: (75-50)/50 x 100 = 50%.
Why is a 50% decrease followed by a 50% increase not the same as the original?
Because the base changes. If $100 decreases by 50%, you have $50. A 50% increase on $50 gives you $75, not $100. To return to the original after a 50% decrease, you need a 100% increase. This asymmetry is important in investing and statistics.
What is the difference between percentage change and percentage points?
Percentage change is the relative change between two values. Percentage points measure the absolute difference between two percentages. A rate going from 5% to 7% is a 2 percentage point increase but a 40% increase in the rate itself.

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