How to Use This Calculator

Three modes cover every common percentage decrease problem. Pick the right one from the dropdown, enter your numbers, and the result appears instantly with a step-by-step breakdown.

Find % decrease between two numbers

The default mode. Enter the original (old) value and the new value. The calculator returns the percentage decrease, absolute change, multiplier, and the percentage of the original that remains. Use this when you already have both figures and need to quantify the drop: a product price before and after a sale, revenue this quarter vs last quarter, a before-and-after weight, or any two numbers where you want the relative decline.

Find new value after % decrease

Enter the original value and the percentage you want to reduce it by. The calculator returns the new value and the amount removed. This is the mode to use for applying a discount to a price, calculating a salary after a pay cut, projecting a population after a known decline rate, or finding any reduced figure when you know the rate of decrease.

Find original value before % decrease

The reverse calculation. Enter the reduced value and the percentage decrease that caused it, and the calculator works backwards to the original. This is useful for auditing: finding a pre-discount price from a sale price, finding last year's revenue from this year's figure and the decline rate, or checking whether a claimed original price is consistent with the sale price and advertised discount.

What Is Percentage Decrease?

Percentage decrease measures how much a value has fallen relative to its starting point, expressed as a percentage. It tells you not just that something went down, but by what fraction of the original it dropped.

Context is everything. A fall of 50 units is a 50% decrease from 100 but only a 5% decrease from 1,000. The absolute number is the same; the percentage decrease depends entirely on the starting value. That is why relative measures like percentage decrease are more informative than raw differences when comparing changes across different scales.

Percentage decrease appears in everyday situations: a shop advertising 30% off, a company reporting a revenue decline, a doctor recording weight loss, a fund manager noting a portfolio drawdown, or a scientist measuring a reduction in a sample. The formula is the same in each case.

Percentage Decrease Formula

Subtract the new value from the original, divide by the original, and multiply by 100.

% Decrease = ((Old Value − New Value) ÷ Old Value) × 100

The result is positive when the value has dropped (old is larger than new) and negative when the value has actually risen. Walk through it step by step: $120 falls to $90. Difference: $120 − $90 = $30. As a fraction: $30 ÷ $120 = 0.25. As a percentage: 0.25 × 100 = 25% decrease.

Finding the new value from a known percentage decrease

Rearrange the formula to calculate a reduced value when you know the original and the percentage drop.

New Value = Original × (1 − Percentage ÷ 100)

Example: a coat priced at $240 is reduced by 35%. New price = $240 × (1 − 35/100) = $240 × 0.65 = $156. The multiplier 0.65 represents the 65% of the price you still pay. Knowing this multiplier lets you calculate discounted prices in a single step, without first finding the discount amount and subtracting separately.

Finding the original value from a percentage decrease

If you know the reduced value and the percentage it was reduced by, divide to recover the original.

Original = New Value ÷ (1 − Percentage ÷ 100)

Example: a sale item is priced at $156 after a 35% reduction. Original = $156 ÷ (1 − 0.35) = $156 ÷ 0.65 = $240. This is the reverse of the forward calculation. It is also the formula retailers use (and regulators audit) to verify that a "was $X, now $Y" claim is consistent with the advertised percentage off.

Percentage Decrease vs Percentage Increase

The formulas are mirrors of each other. Percentage increase uses (new − old) / old. Percentage decrease uses (old − new) / old. Both produce a positive number when the change is in the expected direction.

Here's a trap many people fall into: a 25% increase followed by a 25% decrease does not return to the original. Start at $100. After +25%: $125. After −25% of $125: $125 × 0.75 = $93.75. The decrease is applied to a larger base, so the round trip leaves you below where you started. The same asymmetry applies in reverse: a 25% decrease followed by a 25% increase gives $100 × 0.75 × 1.25 = $93.75, not $100.

This is why recovering from a loss always requires a bigger percentage gain than the loss percentage itself. A 50% drop requires a 100% gain just to break even. A 20% drop requires a 25% gain. The Percentage Increase Calculator covers the increase side of this relationship in full.

Which formula to use

Use percentage decrease when the new value is lower than the original and you want a positive result labelled "decrease." Use the general Percentage Calculator when the direction of change is uncertain and you want a signed result that tells you whether it increased or decreased.

Discounts and Sale Prices

The most common everyday use of percentage decrease is calculating a discounted price. The maths is straightforward once you understand the multiplier approach.

Calculating a discounted price

Multiply the original price by (1 − discount/100). A $80 jacket at 40% off: $80 × 0.60 = $48. No need to first calculate the discount amount ($32) and subtract. The multiplier does it in one step.

Stacked discounts

Two sequential discounts do not add up directly. A 20% discount followed by a further 10% discount: multipliers are 0.80 and 0.90. Combined: $100 × 0.80 × 0.90 = $72, a total reduction of 28%, not 30%. Stacked discounts always give a smaller total reduction than the sum of the individual rates, because each subsequent discount is applied to an already-reduced price.

Finding the original "was" price

A common pricing audit scenario: a product is labelled "Sale $63, was $90." Claimed discount: ($90 − $63) ÷ $90 × 100 = 30%. Verification using the reverse formula: $63 ÷ (1 − 0.30) = $63 ÷ 0.70 = $90. ✓ The claim is consistent. If the reverse formula gives a different "original" than the one advertised, the discount percentage is wrong.

Price and Revenue Decreases

In business, tracking percentage changes in prices and revenue is a core reporting task. The percentage decrease formula applies directly.

Revenue decline

A company reports $2.8 million revenue this quarter, down from $3.5 million last quarter. Decrease: ($3.5M − $2.8M) ÷ $3.5M × 100 = $0.7M ÷ $3.5M × 100 = 20% decline. This figure goes into management reporting, investor communications, and year-over-year comparisons.

Price reduction impact on margin

Cutting price by a percentage reduces revenue by that same percentage only if unit volume stays constant. If a 10% price cut increases units sold by 12%, net revenue change: 1.12 × 0.90 = 1.008, a tiny 0.8% net increase. The Profit Margin Calculator shows how price changes flow through to gross margin once cost of goods stays fixed.

Cost reduction targets

A supply chain team needs to cut procurement costs by 15%. Current spend: $480,000. Target: $480,000 × (1 − 0.15) = $480,000 × 0.85 = $408,000. The savings target is $72,000. Framing goals this way makes the required absolute saving explicit, which is more useful for budgeting than the percentage alone.

Percentage Decrease in Excel

Excel handles percentage decrease with a single formula. Assume old value is in A2 and new value is in B2.

Basic percentage decrease formula

=(A2-B2)/A2. Format the cell as "Percentage" and Excel displays the result as a percentage automatically. This formula returns a positive number when the value has fallen and a negative number when it has risen.

Signed change (positive for increase, negative for decrease)

=(B2-A2)/A2. This version follows the convention used in most financial reporting: negative values indicate declines, positive values indicate growth. The two formulas return the same magnitude but opposite signs.

New value after a percentage decrease

Old value in A2, percentage decrease in C2 (entered as 25, not 0.25): =A2*(1-C2/100). If C2 is formatted as a percentage (you typed 25% directly): =A2*(1-C2). Both return the same result.

Original value from a reduced amount

Reduced value in B2, percentage decrease in C2: =B2/(1-C2/100). This reverses the discount and recovers the original price or value. Useful for auditing marked-down prices or back-calculating last period's figures.

Year-over-year decline in a data column

If monthly figures are in column B from B2 downward, year-over-year change for B14 vs B2: =(B14-B2)/B2. Format as percentage. A negative result means a decline. Wrap in IFERROR(..., "") to handle empty cells at the end of a range cleanly.

For the full range of percentage formulas in Excel, the Percentage Calculator article covers all five problem types including percentage of a number and percentage difference.

Worked Examples

Example 1: Retail Discount

A television originally priced at $850 is on sale for $595. What is the percentage decrease?

($850 − $595) ÷ $850 × 100 = $255 ÷ $850 × 100 = 30% decrease. The customer saves $255, which is exactly 30% of the original $850 price.

Example 2: Salary After a Pay Cut

An employee earns $72,000 and takes a 12% temporary pay cut. What is the new salary?

New salary = $72,000 × (1 − 12/100) = $72,000 × 0.88 = $63,360. The reduction is $8,640 per year. To restore the original salary from $63,360 requires a 13.64% raise (not 12%), because the raise percentage is applied to the lower base.

Example 3: Revenue Year-Over-Year

A business had $1.2 million revenue last year and $960,000 this year. What is the percentage decrease?

($1,200,000 − $960,000) ÷ $1,200,000 × 100 = $240,000 ÷ $1,200,000 × 100 = 20% decrease. Revenue has contracted by a fifth year on year.

Example 4: Finding the Original Price Before a Discount

A sale item costs $42 after a 40% reduction. What was the original price?

Original = $42 ÷ (1 − 40/100) = $42 ÷ 0.60 = $70.00. Verify: $70 × 0.60 = $42. ✓

Example 5: Stock Portfolio Drawdown

A portfolio falls from $24,500 to $19,110. What is the percentage decrease, and what percentage gain is needed to recover?

Decrease: ($24,500 − $19,110) ÷ $24,500 × 100 = $5,390 ÷ $24,500 × 100 = 22% drawdown. Recovery gain needed: $24,500 ÷ $19,110 − 1 = 1.2820 − 1 = 28.2% gain on the current lower value. A 22% loss always requires more than a 22% gain to break even.

Frequently Asked Questions

How do you calculate percentage decrease?

Subtract the new value from the old, divide by the old, and multiply by 100. Formula: ((Old − New) ÷ Old) × 100. Example: from 200 to 150, the decrease is (200 − 150) ÷ 200 × 100 = 50 ÷ 200 × 100 = 25%.

How do you calculate a decrease in percentage between two numbers?

Use ((Old − New) ÷ Old) × 100. The old number is the reference point in the denominator. From 500 to 380: (500 − 380) ÷ 500 × 100 = 120 ÷ 500 × 100 = 24%. The result is positive because the value fell.

What is the formula for percentage decrease?

% Decrease = ((Old Value − New Value) ÷ Old Value) × 100. This is the positive-result version specific to decreases. It is equivalent to the general percentage change formula (New − Old) ÷ Old × 100, except that formula returns a negative number for a decrease. Both measure the same thing; the sign convention differs.

How do you calculate percentage decrease in Excel?

With old value in A2 and new value in B2: =(A2-B2)/A2 returns a positive percentage for a decrease. Format as Percentage. Alternatively, =(B2-A2)/A2 uses the standard signed convention where negative = decrease, positive = increase. To apply a known percentage decrease to a value: =A2*(1-C2/100) where C2 holds the percentage.

How do you calculate a percentage decrease in price?

Same formula: ((Original Price − Sale Price) ÷ Original Price) × 100. Original $120, sale $84: ($120 − $84) ÷ $120 × 100 = $36 ÷ $120 × 100 = 30% price decrease. To apply a discount to a price: multiply by (1 − discount/100). A 30% discount on $120: $120 × 0.70 = $84.

How do you calculate percentage decrease in salary?

Use current salary as "old" and new (lower) salary as "new." Old salary $75,000, new salary $67,500: ($75,000 − $67,500) ÷ $75,000 × 100 = $7,500 ÷ $75,000 × 100 = 10% decrease. To find a reduced salary from a known cut percentage: new salary = current × (1 − cut% ÷ 100).

How is percentage decrease different from percentage increase?

The formulas differ only in the numerator. Decrease: (Old − New) ÷ Old. Increase: (New − Old) ÷ Old. Both give the magnitude of the relative change. Decrease gives a positive result when the value falls; increase gives a positive result when it rises. They are not interchangeable for the same data point: a 25% decrease and a 25% increase produce different absolute values on the same starting number.

What percentage increase is needed to reverse a percentage decrease?

Always more than the original decrease percentage. If a value falls by x%, the recovery gain needed is x ÷ (100 − x) × 100. A 20% fall needs: 20 ÷ 80 × 100 = 25% gain. A 50% fall needs 100% gain. A 75% fall needs 300% gain. The reason is asymmetry: the gain is applied to a smaller base than the loss was.

How do you calculate percentage decrease between two numbers in Excel?

With old in A2 and new in B2: =(A2-B2)/A2 formatted as percentage gives the decrease as a positive number. To flag both increases and decreases: use =(B2-A2)/A2 (negative = fell, positive = rose), apply conditional formatting to colour negative values red. Use ABS() around the formula if you want the magnitude without a sign.

Can percentage decrease be more than 100%?

Not for a standard value that starts positive and stays above zero. A 100% decrease means the value fell to exactly zero. If a value goes negative (for example a profit turning into a loss), the formula still works mathematically and can produce numbers above 100%, but in that context "percentage decrease" is less meaningful than "percentage change." For negative starting values, the sign convention can produce counterintuitive results.

How do you calculate percentage decrease in revenue or sales?

Use last period's revenue as "old" and this period's as "new." Revenue fell from $4.2M to $3.36M: ($4.2M − $3.36M) ÷ $4.2M × 100 = $0.84M ÷ $4.2M × 100 = 20% decline. Report it as "revenue decreased by 20% year-over-year." For context on how this flows through to margin, the Gross Profit Calculator shows the effect of revenue changes on gross profit when cost of goods stays fixed.

References

Khan Academy: Percent Change Review: Worked examples covering percentage increase and decrease with step-by-step solutions and practice problems.
Microsoft Support: Calculate Percentage Change in Excel: Official documentation on percentage change formulas in Excel, including both increase and decrease scenarios.
U.S. Bureau of Labor Statistics: Computing Price Changes: How the BLS calculates percentage changes in prices, with the formula applied to real Consumer Price Index data.

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