How to use
- Enter the starting value.
- Enter the lower ending value.
- Read the percent decrease. If the end is higher, the calculator tells you it is an increase.
Worked example: Weight from 200 lb to 185 lb
The drop is 200 − 185 = 15. Divided by the start, 15 ÷ 200 = 0.075, a 7.5% decrease.
Getting back from 185 to 200 would be a 15 ÷ 185 = 8.11% increase. The percentage is larger on the way up because the base is smaller.
Frequently asked questions
What is the percent decrease formula?
(start − end) ÷ |start| × 100. From 200 to 150 is a 25% decrease.
What if the value went up?
The result is negative and the calculator flags it as an increase. Use the percent increase tab instead.
How do I subtract a percent from a number?
Multiply by (1 − percent ÷ 100). 200 reduced by 25% is 200 × 0.75 = 150.
Can a decrease be more than 100%?
Only if the end value is negative, for example from 50 to −25 is a 150% decrease.
Is this the same as a discount?
The math is the same. The discount calculator adds stacked discounts and sales tax for prices.
Does it round?
Display is rounded to 4 decimals; the calculation is exact.