Percentage Decrease Calculator
Find the percent decrease between an old and a new value, subtract a percent from a number, find the original number before a decrease, or see what repeated decreases add up to. Every answer shows the steps and how much of an increase it takes to get back. It runs in your browser, so nothing you enter is stored.
Calculate
Result
Steps
| Period | Value | Decrease |
|---|
Quick answer
Percentage decrease tells you how much a value has fallen compared with where it started. Subtract the new value from the old value, divide by the old value and multiply by 100. For example, going from 80 down to 60 is a 25 percent decrease.
Use the calculator above for the four most common jobs: finding the percent decrease between two numbers, subtracting a percent from a number, finding the original number before a decrease, and working out repeated decreases over several periods. Each result also shows the increase you would need to get back to the starting value.
How to calculate percentage decrease
Follow these three steps. Here a phone drops in price from 250 to 185.
- Subtract the new value from the original value. 250 minus 185 is 65.
- Divide that change by the original value. 65 divided by 250 is 0.26.
- Multiply by 100 to turn it into a percentage. 0.26 times 100 is 26 percent.
The price fell by 26 percent. Always divide by the original value, the one you started from. If you divide by the new value instead, you get 35.14 percent, which is wrong.
Percentage decrease formulas
| What you want | Formula |
|---|---|
| Percentage decrease between two values | (original – new) / original x 100 |
| Decrease amount | original x percent / 100 |
| New value after subtracting a percent | original x (1 – percent / 100) |
| Original value before a decrease | final value / (1 – percent / 100) |
| Value after repeated decreases | start x (1 – percent / 100) ^ periods |
| Increase needed to get back | (1 / (1 – percent / 100) – 1) x 100 |
The part in brackets, 1 minus the percent as a decimal, is the multiplier. A 15 percent decrease has a multiplier of 0.85, and a 5 percent decrease has a multiplier of 0.95.
Percentage decrease examples
| Situation | Old | New | Change | Decrease |
|---|---|---|---|---|
| Phone price | 250 | 185 | 65 | 26% |
| Monthly spending | 1,500 | 1,275 | 225 | 15% |
| Website visitors | 4,000 | 3,000 | 1,000 | 25% |
| Town population | 12,500 | 12,000 | 500 | 4% |
| Test score | 80 | 64 | 16 | 20% |
| Share price | 50 | 42 | 8 | 16% |
Type any of these into the calculator to see the steps. The same method works for prices, costs, weight, sales, subscribers, temperatures and anything else that can fall.
How to subtract a percentage from a number
To decrease a number by a percent, multiply it by the multiplier. To take 15 percent off 250, multiply 250 by 0.85. The answer is 212.5. The decrease is 37.5, which is 15 percent of 250.
| Decrease | Multiplier | 80 becomes |
|---|---|---|
| 5% | 0.95 | 76 |
| 10% | 0.90 | 72 |
| 15% | 0.85 | 68 |
| 20% | 0.80 | 64 |
| 25% | 0.75 | 60 |
| 50% | 0.50 | 40 |
This is the same method used for discounts, a pay cut, a budget cut or a weight loss target. Choose the Subtract a percent mode in the calculator to do it with steps.
How to find the original number before a decrease
Sometimes you know the final value and the percentage decrease, and you want the number you started with. Divide the final value by the multiplier.
A price is now 68 after a 15 percent decrease. The multiplier is 0.85, so the original price was 68 divided by 0.85, which is 80.
A common mistake is to add 15 percent to 68. That gives 78.2, which is wrong, because the 15 percent was taken from the original 80, and 15 percent of 68 is a smaller amount than 15 percent of 80. Use the Find the original mode to avoid this.
Repeated percentage decreases
When a value falls by the same percent in each period, such as a car that loses 10 percent of its value every year, each period decreases the value that the last period left behind. Multiply the start by the multiplier once for every period.
Starting with 1,000 and taking off 10 percent three times gives 1,000 times 0.9 times 0.9 times 0.9, which is 729. The total decrease is 27.1 percent, not 30 percent, because each year the 10 percent is taken from a smaller amount. The Repeat over time mode shows the value after every period in a table.
How much increase do you need to get back
A decrease and an increase of the same size do not cancel out. If 100 falls by 20 percent it becomes 80. To climb back to 100 you need to add 20, and 20 is 25 percent of 80, so you need a 25 percent increase.
| Decrease | Increase needed to recover |
|---|---|
| 10% | 11.11% |
| 20% | 25% |
| 25% | 33.33% |
| 50% | 100% |
| 75% | 300% |
The bigger the fall, the bigger the climb. This is why large losses are hard to recover from. The calculator shows the increase needed for every result. For the other direction, use our percentage increase calculator.
Percentage points and percentage decrease
Percentage points and percent are not the same thing. If an interest rate moves from 8 percent to 6 percent, it falls by 2 percentage points. That is a 25 percent decrease in the rate, because 2 divided by 8 is 0.25. When you read news about rates, taxes or poll results, check which of the two is meant.
Special cases
- The original value is 0. The percentage decrease cannot be worked out, because the formula divides by 0.
- The new value is 0. The decrease is exactly 100 percent, because everything is gone.
- The new value is larger. The answer is negative, which is an increase. The calculator shows the size of the rise.
- The two values are the same. The decrease is 0 percent.
- The original value is negative. The formula uses the size of the original value. Read these results with care, because a percent change from a negative number can be confusing.
Quick mental maths for percent decreases
You can often take off a percent in your head. Ten percent of a number is found by moving the decimal point one place to the left, so 10 percent of 80 is 8. Five percent is half of that, which is 4. Twenty percent is double the 10 percent amount, which is 16. Twenty five percent is a quarter of the number, which is 20. Subtract the amount you found from the original number to get the new value. For 80 minus 25 percent, take off 20 to get 60.
Where percentage decrease is used
You will meet percentage decrease in everyday money and in work. It is used for discounts and price cuts, falling costs, weight loss, drops in sales or website visitors, population decline, lower test scores and falling share prices. Seeing a change as a percentage makes it easier to compare, because a drop of 50 on a price of 100 is large, while a drop of 50 on a price of 10,000 is small.
Common mistakes
- Dividing by the new value instead of the original value.
- Mixing up percentage points and percent.
- Adding the percent to the final value to find the original number.
- Adding successive decreases instead of multiplying the multipliers.
- Thinking a 20 percent decrease and a 20 percent increase cancel out.
- Rounding too early. Keep the full number until the last step.
Frequently asked questions
How do I calculate percentage decrease?
Subtract the new value from the original value, divide the result by the original value, then multiply by 100. For example, from 80 down to 60 the change is 20, 20 divided by 80 is 0.25, and 0.25 times 100 is 25, so the decrease is 25 percent.
What is the percentage decrease formula?
Percentage decrease = (original value – new value) / original value x 100. You always divide by the original value, because the decrease is measured against where you started.
How do I subtract a percentage from a number?
Multiply the number by 1 minus the percentage as a decimal. To take 15 percent off 250, multiply 250 by 0.85 to get 212.5. You can also find 15 percent of 250, which is 37.5, and subtract it from 250.
How do I find the original number before a decrease?
Divide the final value by 1 minus the percentage as a decimal. If a price is 68 after a 15 percent decrease, the original was 68 divided by 0.85, which is 80. Do not add 15 percent to 68, because the percentage was taken from the larger original number.
Can a percentage decrease be more than 100 percent?
For positive numbers, no. A decrease of 100 percent means the value falls to 0, and you cannot lose more than everything. A value can only fall by more than 100 percent if it moves below zero, for example from 10 to minus 10, which is a 200 percent decrease.
What if the new value is larger than the original?
Then the value went up, not down. This calculator shows the result as an increase and gives the size of the rise. For a full set of increase tools, use our percentage increase calculator.
Why can I not use 0 as the original value?
The formula divides by the original value, and dividing by 0 is not possible. A change from 0 to any other number has no percentage decrease, so the calculator asks for a different starting value.
What is the difference between percentage decrease and percentage points?
Percentage points are the plain difference between two percentages. If a rate falls from 8 percent to 6 percent, that is 2 percentage points, but it is a 25 percent decrease in the rate, because 2 divided by 8 is 0.25.
Why does a 20 percent decrease followed by a 20 percent increase not give back the original?
The increase is applied to a smaller number. If 100 falls by 20 percent it becomes 80, and 20 percent of 80 is only 16, so you reach 96. To get from 80 back to 100 you need an increase of 25 percent.
How do I calculate percentage decrease in Excel or Google Sheets?
If the old value is in A2 and the new value is in B2, type =(A2-B2)/A2 in another cell and format the cell as a percentage. To take a percentage off a number, use =A2*(1-15%).
Is a discount the same as a percentage decrease?
Yes. A discount is a percentage decrease in a price. A 20 percent discount on 50 gives a sale price of 40. For prices with a sale and tax, you can also use our discount calculator.
Is my data saved or sent anywhere?
No. All calculations happen in your browser on your own device. Nothing you type is stored or sent to a server.
About this calculator
Written by Umar Khan. The calculator uses the standard formulas shown on this page and rounds results to four decimal places at most. It works with whole numbers and decimals, and it runs in your browser, so nothing you enter is stored or sent.
About the author
Umar Khan is a PhD student in engineering at NTNU. He writes and checks the maths on UtilMora.
For information only, not professional advice.
Written by Umar Khan. Last updated: November 1, 2026.