The formula, and how to read the answer
percent decrease = ((new value - old value) / old value) x 100
This is the same percent change formula used for increases. The only difference is what the answer looks like: when the new value is smaller, the subtraction gives a negative number, and the final answer is negative. A result of -20 percent is read as "a 20 percent decrease." The minus sign is not a second piece of information; it is just the math telling you the value went down.
Example 1: a price markdown
A jacket falls from $80 to $64. Step one: 64 - 80 = -16. Step two: -16 / 80 = -0.20. Step three: -0.20 x 100 = -20 percent. The jacket is 20 percent off. Working backward confirms it: 80 x 0.80 = 64.
Example 2: a stock drop
A stock falls from $120 to $84. Step one: 84 - 120 = -36. Step two: -36 / 120 = -0.30. Step three: -0.30 x 100 = -30 percent. The stock dropped 30 percent.
Notice the recovery math: getting back to $120 from $84 needs a $36 gain measured against $84, which is a 42.9 percent increase. A 30 percent loss needs more than a 30 percent gain to undo, because the second percentage is measured against the smaller number.
Example 3: weight loss as a percentage
Body weight goes from 190 pounds to 171 pounds. Step one: 171 - 190 = -19. Step two: -19 / 190 = -0.10. Step three: -0.10 x 100 = -10 percent. That is a 10 percent decrease in body weight.
Example 4: a falling rate
A website's bounce rate improves from 70 percent to 56 percent. Step one: 56 - 70 = -14. Step two: -14 / 70 = -0.20. Step three: -0.20 x 100 = -20 percent. The bounce rate fell 20 percent.
Be careful with the wording here: the rate fell 14 percentage points, which is a 20 percent decrease relative to where it started. Percentage points and percent are different answers. Our percentage points vs percent guide explains when to use each.
The asymmetry every decrease hides
The most misunderstood property of percent decrease is that it is not undone by an equal percent increase. A $100 value that drops 50 percent lands at $50; a 50 percent increase from $50 lands at $75, not $100. Getting back to $100 requires a 100 percent gain. The bigger the loss, the harder the recovery: a 90 percent drop needs a 900 percent gain to break even. Investors, shoppers, and headline writers all trip on this, which is why the formula matters more than the intuition.
Check your own numbers. Enter the old and new values and get the percent decrease instantly, with the steps shown.
Try the free percent change calculatorPercent decrease questions, answered
What is the formula for percent decrease?
The formula is ((new value - old value) / old value) x 100. When the new value is smaller, the answer is negative, and the size of the negative number is the percent decrease. For a price falling from $80 to $64: (64 - 80) / 80 x 100 = -20 percent, so the decrease is 20 percent.
How do you say a negative percent change as a decrease?
Drop the minus sign and say decrease. A result of -20 percent is a 20 percent decrease. The negative sign is just the math's way of telling you the value went down.
Can percent decrease be more than 100 percent?
For ordinary positive values, no: a 100 percent decrease takes you to zero, and you cannot lose more than everything. With negative starting values, like profits turning into losses, percentages beyond 100 percent can appear, but the result needs careful interpretation.
Why does a 50 percent drop need a 100 percent gain to recover?
Because the percentages are measured against different starting values. A $100 stock falling 50 percent lands at $50, and a gain from $50 is measured against $50, so it needs to double: a 100 percent gain. Losses and gains are not symmetric.
How do you calculate percent decrease in Excel?
Put the old value in A1 and the new value in B1, then enter =(B1-A1)/A1 and format as a percentage. The result will be negative when the value fell, and the size of the number is the percent decrease.