Percentage Decrease Calculator
Find out how much a value has dropped in percentage terms. Enter the original value and the new value to get the percentage decrease.
Enter values to calculate.
How to calculate
Percentage decrease measures how much a value has shrunk relative to where it started: ((original value − new value) ÷ original value) × 100. Use it for discounts, weight loss, falling prices, or any comparison where you want the drop expressed as a share of the starting point rather than a raw amount.
By hand, subtract the new value from the original to get the drop, divide by the original, then multiply by 100. Dropping from 120 to 90: the drop is 30, divide by 120 to get 0.25, multiply by 100 for a 25% decrease.
Percentage decreases can't exceed 100% — a value can only fall to zero, not below it, in percentage terms. But recovering a loss takes a bigger percentage than the loss itself: a 50% decrease needs a 100% increase to get back to the starting value, because the increase is calculated from a smaller base.
Examples
- From 100 to 80: ((100 − 80) ÷ 100) × 100 = 20% decrease.
- From 60 to 45: ((60 − 45) ÷ 60) × 100 = 25% decrease.
- From 45 to 27: ((45 − 27) ÷ 45) × 100 = 40% decrease.
- From 500 to 350: ((500 − 350) ÷ 500) × 100 = 30% decrease.
Frequently asked questions
- What is the percentage decrease formula?
- Subtract the new value from the original value, divide by the original value, then multiply by 100.
- Is percentage decrease the same as percentage change?
- It is the same magnitude, but a decrease is shown as a positive number here, whereas percentage change keeps the sign (negative for a drop).
- If something is discounted 50% twice, is that the same as 100% off?
- No. Applying 50% off twice is not 100% off — it's 75% off total. The first 50% takes $100 to $50; the second 50% takes $50 to $25, a total drop of 75%, not 100%. Each percentage decrease is calculated from the new, already-reduced value, not the original.
- Can a percentage decrease ever be more than 100%?
- No — a value can fall to zero at most, which is a 100% decrease. Anything described as 'more than 100% down' isn't mathematically valid for percentage decrease, unlike percentage increase which has no upper limit. If a number goes negative, use percentage change instead, which allows a signed result beyond ±100%.