Percentage Decrease Calculator
Enter an original value and a new value to find the percent decrease, the amount lost, and the new value as a share of the original. Results update as you type.
Formula: Percent Decrease = ((Original − New) ÷ Original) × 100
What Is Percentage Decrease?
Percentage decrease measures how much a quantity has fallen, expressed as a fraction of the original amount rather than as a raw difference. The raw difference is the absolute decrease: the literal number of dollars, units, or people lost. The percentage version is the relative decrease, and it is what makes comparison across different scales possible. A drop of $5 means very different things when the starting price is $10 versus $1,000, and only the percentage form makes that clear.
Three terms recur whenever you work with this calculation: the Original Value, also called the Starting Value (the point you begin from and the base of the formula), the Final Value (sometimes called the New Value, where the quantity ended up), and the Rate of Decrease (the percentage itself). Together they describe the Relative Change between two states. The original value is always the denominator, so choosing the wrong base is the single most common source of incorrect percent-decrease answers.
Percentage decrease matters because almost every comparison in finance, retail, and science is relative. Investors care about a 12% drop in a stock, not the exact dollar change. Shoppers respond to a 40% discount, not the raw saving. Public health teams report a 7% decline in case counts to make changes comparable across regions of different size. In every case the percentage carries more meaning than the absolute number.
Percentage Decrease Formula
The standard formula is:
Every variable has a fixed role. Original is the earlier or larger value and serves as the base. New is the later or smaller value. The absolute-value bars around the original handle the rare case of negative starting values so that the sign of the result still reads correctly as a decrease. The multiplication by 100 converts the decimal fraction into the percentage form people read on price tags and financial reports.
The derivation is straightforward. The change is Original − New. To make that change comparable across different scales, divide by the size of what you started with. That ratio is the relative change as a decimal between 0 and 1. Multiplying by 100 just rewrites the same decimal in percentage units. When the new value is greater than the original, the numerator is negative and the formula returns a negative percent, a signal to switch to the percentage increase formula instead.
In Excel or Google Sheets the equivalent expression is =((A1-B1)/ABS(A1))*100 where A1 is the original value and B1 is the new value. The ABS function protects you from sign errors when A1 might be negative.
How to Calculate Percentage Decrease
Step 1 – Find the Difference Between Values
Subtract the new value from the original. With an original of 200 and a new value of 150, the difference is 200 − 150 = 50.
Step 2 – Divide by the Original Value
Divide the difference by the absolute value of the original: 50 ÷ 200 = 0.25.
Step 3 – Multiply by 100
Convert the decimal to a percentage: 0.25 × 100 = 25%.
Step 4 – Interpret the Result
A 25% decrease means the new value is 75% of the original. If the answer is negative, the new value rose instead of fell; treat it as an increase.
Common Calculation Mistakes
The most frequent error is using the new value as the base. A drop from 200 to 150 is 25%, not 33.3%. The second is forgetting to express the answer as a percentage. The third is averaging two percent changes from different periods, which double-counts in the wrong direction; chain the multipliers instead.
Percentage Decrease Examples
Example 1 – Price Reduction (product from $200 to $150)
((200 − 150) ÷ 200) × 100 = 25% decrease. The shopper saves $50.
Example 2 – Salary Reduction ($85,000 to $72,000)
((85000 − 72000) ÷ 85000) × 100 ≈ 15.29% reduction, a loss of $13,000 per year.
Example 3 – Population Decline (town from 12,000 to 10,800)
((12000 − 10800) ÷ 12000) × 100 = 10% decline, a loss of 1,200 residents.
Example 4 – Revenue Drop ($1,000,000 to $750,000)
((1000000 − 750000) ÷ 1000000) × 100 = 25% revenue drop of $250,000.
Example 5 – Weight Loss (200 lbs to 185 lbs)
((200 − 185) ÷ 200) × 100 = 7.5% decrease, 15 pounds lost.
Example 6 – Fuel Price Reduction ($4.20 to $3.78 per gallon)
((4.20 − 3.78) ÷ 4.20) × 100 = 10% drop, saving 42 cents per gallon.
Example 7 – Stock Price Decrease ($340 to $289)
((340 − 289) ÷ 340) × 100 = 15% drop, $51 per share.
Example 8 – Website Traffic Drop (48,000 to 31,200 monthly visits)
((48000 − 31200) ÷ 48000) × 100 = 35% traffic drop, 16,800 visits lost.
Percentage Decrease vs Percentage Change
Percentage change is the broader concept: the signed relative difference between two values. Percentage decrease is the unsigned size of a change that points downward. Use percentage change when the direction matters in the answer itself (financial reporting, dashboards). Use percentage decrease when you already know the value fell and want to communicate how much by. A change of −20% and a decrease of 20% describe the same fact in different reading styles.
Percentage Decrease vs Percentage Increase
The two are mirror calculations. Percentage increase uses ((New − Original) ÷ Original) × 100, with the new value larger than the original. A common misconception is that a 50% decrease followed by a 50% increase returns you to the starting point. It does not: 100 → 50 → 75, because the second percentage is taken from a smaller base. The order, the base, and the direction all matter.
| Operation | Formula | Example (100 → 80) |
|---|---|---|
| Increase | ((New − Old) ÷ Old) × 100 | +25% (80 → 100) |
| Decrease | ((Old − New) ÷ Old) × 100 | 20% (100 → 80) |
Percentage Decrease vs Percentage Difference
Percentage difference uses the formula |V1 − V2| ÷ ((V1 + V2) ÷ 2) × 100. It is symmetric: the order of the two values does not change the answer, because it divides by their average instead of by one specific value. Use difference when neither value is naturally the base (comparing two measurements of the same thing). Use decrease when there is a clear original and a later, smaller value.
How to Calculate a New Value After a Percentage Decrease
The reverse direction uses the formula New = Original × (1 − Rate/100). A 30% decrease on $250 leaves 250 × 0.70 = $175. This reverse percentage calculation also works to recover an original price from a discounted price: divide instead of multiply. A shirt at $42 after a 30% reduction started at 42 ÷ 0.70 = $60. The same reverse percentage algebra recovers inflation-adjusted values and undoes any single-step reduction.
Percentage Multipliers
A multiplier is the one-step factor for a percentage change. For a decrease, subtract the rate from 1: 20% off gives a 0.80 multiplier; 15% off gives 0.85.
| Decrease | Multiplier |
|---|---|
| 5% | 0.95 |
| 10% | 0.90 |
| 15% | 0.85 |
| 20% | 0.80 |
| 25% | 0.75 |
| 30% | 0.70 |
| 40% | 0.60 |
| 50% | 0.50 |
| 75% | 0.25 |
Percentage Decrease Table
| Original | Decrease | Amount | New Value |
|---|---|---|---|
| 100 | 5% | 5 | 95 |
| 100 | 10% | 10 | 90 |
| 100 | 15% | 15 | 85 |
| 100 | 20% | 20 | 80 |
| 100 | 25% | 25 | 75 |
| 100 | 30% | 30 | 70 |
| 100 | 50% | 50 | 50 |
| 100 | 75% | 75 | 25 |
| 500 | 5% | 25 | 475 |
| 500 | 10% | 50 | 450 |
| 500 | 15% | 75 | 425 |
| 500 | 20% | 100 | 400 |
| 500 | 25% | 125 | 375 |
| 500 | 30% | 150 | 350 |
| 500 | 50% | 250 | 250 |
| 500 | 75% | 375 | 125 |
| 1,000 | 5% | 50 | 950 |
| 1,000 | 10% | 100 | 900 |
| 1,000 | 15% | 150 | 850 |
| 1,000 | 20% | 200 | 800 |
| 1,000 | 25% | 250 | 750 |
| 1,000 | 30% | 300 | 700 |
| 1,000 | 50% | 500 | 500 |
| 1,000 | 75% | 750 | 250 |
| 5,000 | 5% | 250 | 4,750 |
| 5,000 | 10% | 500 | 4,500 |
| 5,000 | 15% | 750 | 4,250 |
| 5,000 | 20% | 1,000 | 4,000 |
| 5,000 | 25% | 1,250 | 3,750 |
| 5,000 | 30% | 1,500 | 3,500 |
| 5,000 | 50% | 2,500 | 2,500 |
| 5,000 | 75% | 3,750 | 1,250 |
Real-Life Applications of Percentage Decrease
Retail Price Reductions
Retailers plan seasonal markdowns as a sequence of percentage decreases. A jacket marked down 30%, then a further 20% off the new price, ends at 100 × 0.70 × 0.80 = 56% of the original: a 44% total reduction, not 50%. Inventory teams use the same arithmetic in retail markdown planning, setting clearance schedules and end-of-season targets around seasonal inventory reduction metrics rather than guesswork.
Business Revenue Analysis
Quarterly reports compare current performance to the same quarter a year earlier so that seasonality cancels out. A 6% drop in quarterly revenue is a meaningful change; the absolute dollar figure rarely is on its own. Pre-tax profit shrinkage, gross margin compression, and cost reductions are all reported as percent changes for the same reason.
Stock Market Declines
Share prices and index levels are quoted with percent changes because the dollar moves on a high-priced share like Berkshire are not comparable to dollar moves on a $20 stock. Portfolio value tracking uses the same logic: a 15% drawdown is a drawdown whether the portfolio is $5,000 or $5,000,000.
Population Change Studies
Demographers report decline rates per decade. Japan, Italy, and several Eastern European countries have measured negative percentage population changes for years. Expressing the change as a percentage makes Tokyo and a small village comparable.
Weight Loss Tracking
Body mass reduction is more meaningful as a percent of starting weight than as a number of pounds, because a 10-pound loss is significant for a smaller person and modest for a larger one.
Science and Statistics
Experimental data changes, measurement variations, and relative error are all reported as percentage decreases or increases. The percentage form makes results from instruments of different scales directly comparable.
Percentage Drop, Decline and Reduction in Everyday Use
"Percentage drop", "percentage decline" and "percentage reduction" are everyday synonyms for percentage decrease. A retailer announces a 25% percentage drop in clearance prices, a demographer reports a 1.2% annual percentage decline in rural populations, and an energy team measures the percentage reduction from a 60-watt incandescent bulb to an 8-watt LED light bulb: an 86.67% cut in power draw. Demographic trends in Japan, Italy, and Eastern Europe are tracked as multi-year percentage declines. Retail price reductions during seasonal sales, weight loss measured as a percentage of starting body mass, freelance rate adjustments during slow quarters, and stock pullbacks reported as percent drawdowns all rely on the same percentage decrease formula.
Percentage Decrease in Finance
Finance treats percent decrease as the default unit of communication. Year-over-year revenue comparisons, quarter-over-quarter margin contraction, subscription churn, and currency devaluation all use the same formula. A 4% currency devaluation, a 4% drop in monthly recurring revenue, and a 4% portfolio drawdown look identical on paper because the math is identical. That common language is the reason analysts can scan a report quickly and form a picture.
Frequently Asked Questions
What is percent decrease?
Percent decrease is the relative drop from an original value to a smaller new value, expressed as a percentage of the original. It tells you how much something shrank in proportional terms.
How do you calculate percentage decrease?
Subtract the new value from the original, divide that difference by the absolute value of the original, then multiply by 100. The result is the percent decrease.
What is the formula for percentage decrease?
Percent Decrease = ((Original − New) ÷ |Original|) × 100. The original value is always the base, never the new value.
Can percentage decrease be more than 100%?
Yes, but only when the new value is negative. A drop from 50 to −10 is a 120% decrease, because the change (60) is larger than the original (50).
How do I calculate a 20% decrease?
Multiply the original value by 0.80. For example, a 20% decrease on 250 gives 250 × 0.80 = 200.
What is the difference between percent decrease and percent change?
Percent change covers both directions. It returns a positive number for an increase and a negative number for a decrease. Percent decrease is the absolute size of a downward percent change.
What is the difference between percent decrease and percent difference?
Percent decrease is directional and uses the original value as the base. Percent difference is symmetric and uses the average of the two values as the base, so it does not matter which value you list first.
How do I find the original value before a percentage decrease?
Divide the new value by (1 − Rate/100). If a product on sale costs $80 after a 20% reduction, the original price was 80 ÷ 0.80 = $100.
What does a negative percentage decrease mean?
A negative result from the decrease formula means the new value is actually larger than the original, so the change is an increase. Switch to the percentage increase formula.
How do I calculate percentage decrease in Excel?
Use =((A1-B1)/ABS(A1))*100 where A1 is the original value and B1 is the new value. Format the cell as a number, not as a percentage.
How do I calculate percentage decrease per year?
For an annual percentage decrease, apply the formula between this year's value and last year's value. To track percentage decrease over time across several years, compute the compound annual decline rate instead: (End/Start)^(1/years) − 1.
What is a percentage multiplier?
A multiplier is the single factor that produces the new value in one step. For a 30% decrease the multiplier is 0.70; for a 15% decrease it is 0.85.
How do I calculate percentage decrease without a calculator?
Find 10% of the original by moving the decimal one place left, scale it to the rate you need, then subtract. For 25% off 80: 10% is 8, so 25% is 20, and 80 − 20 = 60.
What is percentage reduction?
Percentage reduction is another name for percentage decrease. The two terms are interchangeable in everyday finance and retail.
How do you calculate a price reduction?
Subtract the sale price from the original price, divide by the original price, then multiply by 100. A drop from $50 to $40 is a 20% price reduction.
What is the percentage decrease from 100 to 80?
It is 20%. ((100 − 80) ÷ 100) × 100 = 20.
What is the percentage decrease from 50 to 40?
It is 20%. ((50 − 40) ÷ 50) × 100 = 20.
What is the percentage decrease from 200 to 150?
It is 25%. ((200 − 150) ÷ 200) × 100 = 25.
What is the percentage decrease from 1000 to 750?
It is 25%. ((1000 − 750) ÷ 1000) × 100 = 25.
How is percentage decrease used in business?
Companies measure revenue declines, cost reductions, churn rates, and headcount changes as percentage decreases so that figures stay comparable across periods and units.
How is percentage decrease used in science?
Researchers report shrinkage in samples, error reduction, decay rates, and population declines as percent changes so that small and large studies can be compared on the same scale.
What is a population decline rate?
It is the percent decrease in the number of people in a region between two dates. A town that shrinks from 12,000 to 10,800 has a 10% population decline.
What is the percentage decrease multiplier for 25%?
0.75. Any value multiplied by 0.75 returns the result of a 25% decrease.
Is percent decrease the same as percent off?
Yes. "Percent off" is the retail phrasing of the same calculation: a price multiplied by (1 − Rate/100).
How do you calculate salary reduction as a percentage?
Subtract the new salary from the old salary, divide by the old salary, then multiply by 100. A cut from $85,000 to $72,000 is roughly a 15.29% reduction.