Percentage Decrease Calculator
Calculate the percentage decrease between two values accurately.
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Quick Tip
Enter the original value before the decrease.
About This Tool
Why use Percentage Decrease?
A percentage decrease shows how far a value has fallen compared with where it started: divide the fall by the original value and multiply by 100. This calculator also shows the absolute difference and how much of the original value is retained.
Example: a price cut from 250 to 200 is a fall of 50, and 50 ÷ 250 × 100 = 20%. The retained share is 80%, which is the same as multiplying by 0.8. That retained figure is the quick way to apply the same discount to other prices.
Key Benefits
Decrease and retained value together
A 20% decrease and 80% retained are two ways of saying the same thing; seeing both makes discount and loss calculations quicker to check.
Instant sanity check on discounts
Enter the list price and the sale price to see the true discount, which is often smaller than the headline claim.
Same maths for any unit
Money, weight, traffic or inventory: percentage change does not care about the unit.
How to use Percentage Decrease
- 1
Enter the original value before the decrease.
- 2
Enter the new, lower value.
- 3
Read the percentage decrease and the absolute difference in units.
- 4
Use the retained percentage to apply the same cut to other numbers, or to check a discounted price.
Best use cases
Check the real discount percentage on a sale item.
Report a drop in costs, churn or defect rates.
Measure weight loss or a reduction in usage over a period.
Verify that a quoted price cut matches the numbers on the invoice.
Percentage Decrease FAQs
What is the percentage decrease formula?
Percentage decrease = (original value − new value) ÷ original value × 100. From 250 to 200: 50 ÷ 250 × 100 = 20%.
How do I find the original price before a discount?
Divide the sale price by the retained share. A price of 200 after a 20% discount was 200 ÷ 0.8 = 250 before the discount.
Can a decrease be more than 100%?
Only if the value passes zero and becomes negative — for example a profit that turns into a loss. For prices and quantities the maximum decrease is 100%, which means the value reached zero.
What does retained percentage mean?
It is the share of the original value that is left: new value ÷ original value × 100. A 35% decrease leaves 65% retained.
Related Math Tools
More free math tools that work well alongside percentage decrease.