Percentage Calculator

Calculate discounts, tips, VAT, percentage change, and percentage difference. Results update as you type.

Percentage Change Calculator

Calculate the percent change between two numbers: growth, decline, or any movement from a starting value to a final one. Type the initial value and the final value below; the result is signed (positive for an increase, negative for a decrease) and updates as you type. Common uses: stock returns, year-over-year revenue, KPI deltas, A/B test lifts.

Change fromto?
=
%

How percentage change is calculated

Percentage change measures how far a value has moved relative to where it started. The formula is change = (final − initial) ÷ initial × 100. Because the denominator is the initial value, the order of inputs matters; swapping them flips the sign and the magnitude.

If the initial value is zero the formula is undefined: dividing by zero has no meaningful answer, and "infinite percent growth" is a description, not a number. The calculator surfaces this as an error rather than guessing.

Worked example

A stock opens at $200 and closes at $250. Enter 200 as the initial value and 250 as the final value. The result is +25%. If it had dropped to $150, the result would be −25%: same magnitude, opposite direction.

Percentage Change Calculator FAQ

What's the formula for percentage change?
(final − initial) ÷ initial × 100. The result is positive if the final value is higher than the initial (an increase) and negative if it's lower (a decrease).
How is percentage change different from percentage difference?
Percentage change has direction: an old value and a new value. Percentage difference compares two values symmetrically without an arrow of time. Use change for things like growth rate or stock returns; use difference for comparing two prices, two measurements, or two estimates that don't have a "before" and "after". See the percentage difference calculator.
Why does the calculator error when the initial value is zero?
Because the formula divides by the initial value. "From zero to anything" has no defined percentage. In practice, report this as "new value, up from zero" rather than as a percent.
Can the result be negative?
Yes. A negative result means the value went down. 200 → 150 is −25%; 200 → 250 is +25%. The sign tells you direction, the magnitude tells you size.
How do I apply a known percent change to a starting value?
Use the discount calculator (or the Increase / Decrease by row on the main page): set Increase or Decrease, enter the starting value and the percent.

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