Decreasing by a percentage multiplies the value by one minus that percentage. A 15% decrease multiplies by 0.85.
How to use the Percentage Decrease Calculator
- Original value
- Decrease
- Want to work backwards? Type a value into New value and Decrease is calculated for you.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Multiply the original by one minus the percentage as a decimal. Type the new value into the result to find the percentage.
Inputs explained
| Field | What to enter |
|---|---|
| Original value | A number |
| Decrease | In % |
What each result means
- New value = [Original value] × (1 – [Decrease]÷100)
- Amount removed = [Original value] – [New value]
Example values
How the main result changes when Decrease changes and everything else stays at the example values above:
| Decrease (%) | New value |
|---|---|
| 7.5 | 74 |
| 11.25 | 71 |
| 15 | 68 |
| 18.75 | 65 |
| 22.5 | 62 |
| 30 | 56 |
Formula
New value = original × (1 − decrease ÷ 100)Worked example
Inputs — Original value: 80; Decrease: 15 %.
Results — New value = 68; Amount removed = 12.
Frequently asked questions
Can a decrease be more than 100%?
Not for quantities that cannot go below zero, such as prices.
How is this different from percentage change?
Percentage change handles rises and falls; this tool applies a fall.
What formula does the Percentage Decrease Calculator use?
New value = original × (1 − decrease ÷ 100).
Can I work backwards from the result?
Yes. Type the result you want into New value and the calculator finds the matching decrease.