Percentage Decrease Calculator
Find how much a value dropped as a percentage, work out the price after a percent off, or reverse a discount to find the original price.
25%
Amount decreased
20
Formula With Your Numbers
(80 − 60) ÷ 80 × 100 = 25%Percentage decrease shows how much a value fell compared with where it started: a price drop, a smaller population, a lower score, or weight lost. This calculator has three modes. Find % Decrease compares an original value with a new, lower value. Price After Decrease starts from an original value and a percentage off, and returns the new value and the amount saved. Original Before Decrease works backwards from a final price and the percentage taken off. If your new value is higher than the original, the calculator says so and points you to the percentage increase calculator instead of showing a confusing negative number.
How to Use the Percentage Decrease Calculator
1. Pick a mode
Use Find % Decrease to compare two values, Price After Decrease to apply a percent off, or Original Before Decrease to reverse a discount.
2. Enter your numbers
Type the original and new values, or the value and the percentage, depending on the mode.
3. Read the result
The answer appears with the amount of the change and the formula using your numbers.
4. Copy it
Use the copy button to take the result into a spreadsheet, report, or assignment.
Percentage Decrease Formulas
Percentage decrease
Percentage Decrease = (Original − New) ÷ Original × 100Example: a jacket falling from $80 to $60 is (80 − 60) ÷ 80 × 100 = 25%.
Value after a percentage decrease
New Value = Original × (1 − Percentage ÷ 100)Example: 25% off $80 is 80 × 0.75 = $60, which saves $20.
Original before a percentage decrease
Original = New ÷ (1 − Percentage ÷ 100)Example: a price of $60 after 25% off means the original was 60 ÷ 0.75 = $80.
Percentage Decrease Examples
Each row uses the same formula: subtract the new value from the original, divide by the original, then multiply by 100.
| From | To | Change | Percent decrease |
|---|---|---|---|
| 100 | 80 | −20 | 20% |
| 250 | 200 | −50 | 20% |
| 60 | 45 | −15 | 25% |
| 1,200 | 900 | −300 | 25% |
| 80 | 68 | −12 | 15% |
| 500 | 425 | −75 | 15% |
| 180 | 162 | −18 | 10% |
Percent Off: Price After a Discount
The sale price is the original multiplied by (1 − percent off ÷ 100). Here is a $80 item at common discount levels.
| Percent off | You save | Sale price |
|---|---|---|
| 10% | $8 | $72 |
| 15% | $12 | $68 |
| 20% | $16 | $64 |
| 25% | $20 | $60 |
| 30% | $24 | $56 |
| 40% | $32 | $48 |
| 50% | $40 | $40 |
Percent Decrease Word Problems
A jacket is marked down from $80 to $60. What is the percent decrease?
Answer: 25%
((80 − 60) ÷ 80) × 100A town's population falls from 12,000 to 10,800. What is the percent decrease?
Answer: 10%
((12,000 − 10,800) ÷ 12,000) × 100A person's weight goes from 200 lb to 185 lb. What is the percent decrease?
Answer: 7.5%
((200 − 185) ÷ 200) × 100Why Decreases and Increases Don't Cancel Out
A 50% decrease followed by a 50% increase does not bring you back to the start. From 100, a 50% decrease gives 50, and a 50% increase on 50 gives 75. The increase is applied to a smaller number, so it adds back less than the decrease took away. To recover from a 50% decrease you need a 100% increase.
The same logic applies to stacked discounts. 20% off followed by another 10% off is not 30% off: 100 becomes 80, then 72, a total decrease of 28%. For the opposite direction, try the percentage increase calculator, or compare two values with no clear starting point using the percentage difference calculator.
Frequently Asked Questions
How do you calculate percentage decrease?
Subtract the new value from the original, divide by the original value, then multiply by 100. For example, a drop from 250 to 200 is (250 − 200) ÷ 250 × 100 = 20%.
How do I calculate a decrease in percentage on a calculator?
Put the subtraction in brackets so it happens first, then divide by the original and multiply by 100. For a drop from 250 to 200, key in (250 − 200) ÷ 250 × 100 and you get 20. Without the brackets, most calculators would divide before subtracting and give the wrong answer.
What is the difference between percentage decrease and percentage change?
Percentage change is the general term for movement in either direction. A negative percentage change is a decrease, and a positive one is an increase. This calculator reports a decrease; if your value went up, it tells you and links to the increase calculator.
Can a percentage decrease be more than 100%?
Not for non-negative values. A 100% decrease takes a value to zero, and going beyond that would mean a negative value. If a quantity can go negative, such as a bank balance, percentage decrease stops being meaningful.
How do I calculate the price after a percentage discount?
Multiply the original price by (1 − discount ÷ 100). A 25% discount on $80 is 80 × 0.75 = $60. Use the Price After Decrease mode to do it instantly.
How do I find the original price before a discount?
Divide the final price by (1 − discount ÷ 100). If a coat costs $60 after 25% off, the original price was 60 ÷ 0.75 = $80. The Original Before Decrease mode does this for you.
Why doesn't a 50% decrease followed by a 50% increase return to the start?
Because the increase is calculated on the smaller value. Starting at 100, a 50% decrease gives 50, and a 50% increase on 50 gives 75. To get back to 100 you would need a 100% increase.
How do I calculate percentage increase or decrease in one step?
Use (New − Original) ÷ Original × 100. A positive result is an increase and a negative result is a decrease. For example, 80 to 60 gives −25%, a 25% decrease.
What does a negative percentage decrease mean?
It means the value actually went up. A "−20% decrease" is a 20% increase. This calculator labels it as an increase rather than showing a negative decrease.
Common Mistakes
❌ Dividing by the new value instead of the original
The decrease is always measured against where you started. Going from 80 to 60 is a 25% decrease because 20 ÷ 80 = 0.25, not 20 ÷ 60.
❌ Expecting a decrease and an increase of the same percentage to cancel out
Drop 100 by 50% and you have 50. Increase 50 by 50% and you have 75, not 100. The increase is applied to a smaller number, so it adds back less than the decrease took away.
❌ Adding discounts together instead of stacking them
20% off followed by another 10% off is not 30% off. 100 becomes 80, then 72, so the total decrease is 28%.
❌ Confusing percentage points with percent
A rate falling from 8% to 6% is a 2 percentage-point drop, but a 25% decrease relative to the original rate, since 2 ÷ 8 = 0.25.
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