WorkedMathGlossary

Percentage Decrease Calculator

Enter an original and a new value below to instantly get the percentage decrease.

Percent Decrease
25%
Change of -20 from 80 to 60

The Percentage Decrease Formula

Percentage decrease = (original − new) ÷ original × 100

A common mistake is dividing by the new (smaller) value instead of the original value. That inflates the reported decrease, since the denominator should always be the starting amount you're comparing against, not what's left after the drop.

Worked example

A price drops from $80 to $60.

(80 − 60) ÷ 80 × 100 = 20 ÷ 80 × 100

Percentage decrease = 25%

A second example: inventory drops from 250 units to 200 units.

(250 − 200) ÷ 250 × 100 = 50 ÷ 250 × 100

Percentage decrease = 20%

Keep going

  • Percentage decrease and increase are the same formula with the sign flipped; the percentage increase calculator handles a value going up instead of down. Percentage Increase Calculator
  • A discount is a percentage decrease applied specifically to a price; the discount calculator adds the final price and dollar savings on top of the plain percent change. Discount Calculator

Frequently Asked Questions

What is the percentage decrease formula?

Percentage decrease = (original value − new value) ÷ original value × 100.

Why do some calculators show a negative sign?

Some tools return the raw percent change, which is negative when a value drops. This calculator reports the magnitude of the decrease directly.

Does percentage decrease always use the original value as the base?

Yes. The decrease is always measured relative to the starting value, not the ending value — that's why a 50% decrease followed by a 50% increase doesn't get you back to where you started.

Is a 'percentage point' drop the same as a 'percent' decrease?

No — this trips up a lot of news reporting. If an unemployment rate falls from 8% to 6%, that's a 2 percentage point drop (8 − 6), but relative to the starting rate it's a 25% percentage decrease: (8 − 6) ÷ 8 × 100 = 25%. The two figures answer different questions about the same change.

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