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Percentage Decrease Calculator
Find the percent decrease between two numbers, or reduce a number by a percentage, such as a discount. Both answers update as you type.
Decrease a number by a percentage
Find the percentage decrease between two numbers
The formulas
percentage decrease = (old - new) / old x 100 new value = old x (1 - decrease / 100)
Worked examples
| Question | Working | Answer |
|---|---|---|
| Reduce 200 by 15% | 200 x 0.85 | 170 |
| Percent decrease from 80 to 60 | (80 - 60) / 80 x 100 | 25% |
| $50 item, 30% off | 50 x 0.70 | $35 |
If the new number is larger than the old one, the result shows as an increase. For a rise, use the percentage increase calculator, or the percent change calculator to see either direction.
Frequently asked questions
How do I calculate a percentage decrease?
Subtract the new value from the old value, divide by the old value, and multiply by 100. From 80 to 60 is (80 - 60) / 80 x 100 = 25%.
How do I reduce a number by a percentage?
Multiply it by 1 minus the percentage as a decimal. Reducing 200 by 15% is 200 x 0.85 = 170.
How do I work out a sale price?
Multiply the original price by 1 minus the discount. A $50 item at 30% off costs 50 x 0.70 = $35.
What do two discounts in a row add up to?
They multiply, they do not add. 20% off and then a further 10% off leaves 0.80 x 0.90 = 0.72 of the price, which is 28% off in total, not 30%.
If a value falls 50% and then rises 50%, do I get back to the start?
No. 100 falls to 50, and 50 rising by 50% is only 75. A percentage always applies to the current value, so the rise starts from a smaller number.