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Education & Math

Percentage Decrease Calculator

A price that falls from $80 to $60 has dropped by 25%, because the $20 fall is a quarter of the original $80. This percentage decrease calculator measures how much a value has fallen relative to where it started. Enter the original and new values and get the decrease, the raw difference, and a heads-up if the value actually went up instead.

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Quick answer

Percentage decrease measures a fall relative to the original value.

Percentage decrease

25% decrease

Difference

20

What this tells you

  • Percentage decrease measures a fall relative to the original value.
  • The formula is ((original - new) / original) x 100.
  • The original value is always the base, which is why an $80 to $60 fall is 25% and not 33%.
  • If the result comes out negative, the value increased rather than decreased.

How to Use

  1. 1Enter the original value, the one from before the change.
  2. 2Enter the new, lower value.
  3. 3Read the percentage decrease and the raw difference.
  4. 4If your new value is higher, the tool reports the change as an increase instead.

How It Works

Formula

percentage decrease = ((original - new) / original) x 100

Subtract the new value from the original, divide by the original, and multiply by 100. From 80 to 60 the fall is 20, and 20 / 80 = 0.25, so the decrease is 25%. Reversing the same change, 60 back up to 80, is a 33.3% increase, because the base switches to the smaller number.

Calculation note: values are processed in the order shown above, using the current input units.

Worked Examples

Sale price from $80 to $60

Original Value80
New Value60
Result25% decrease

The $20 cut is a quarter of the original $80 price.

Weight from 200 lb to 170 lb

Original Value200
New Value170
Result15% decrease

The 30 lb loss divided by the 200 lb starting weight gives 0.15.

Website traffic from 8,400 to 6,300 visits

Original Value8400
New Value6300
Result25% decrease

The 2,100-visit drop is exactly a quarter of 8,400.

Percentage Decrease Quick Reference

Original and new values with the resulting decrease.

OriginalNewDecrease
1009010%
1007525%
1005050%
806025%
25020020%
604525%

Common mistakes

  • Dividing by the new value. The original is the base. From 80 to 60 the decrease is 20/80 = 25%, not 20/60 = 33%.
  • Assuming the same percent up undoes a percent down. A 25% decrease from 80 lands at 60, but a 25% increase from 60 only reaches 75.
  • Confusing percentage decrease with percentage points. A rate falling from 12% to 9% dropped 3 points, which is a 25% relative decrease.

Frequently Asked Questions

Subtract the new value from the original, divide by the original, and multiply by 100. From 80 to 60 that is 20 / 80 x 100 = 25%.
25%. The fall is 25, and 25 divided by the original 100 is exactly 0.25.
Because the base is the original 80, not the new 60. The 20-point fall is 25% of 80. It would only be 33% measured against 60, which is the increase going back up.
Only if the value goes negative. A fall from 50 to -10 is a 120% decrease. For values that stop at zero, 100% is the floor.
The formula gives a negative decrease, which this calculator relabels as an increase so the direction is unmistakable.
Yes in structure. A 25% off sale is a 25% price decrease. Percent-off deals just state the decrease up front instead of asking you to compute it.
It estimates percentage decrease calculator outputs using the visible inputs and formula assumptions on this page.

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