Discount calculator

Use this discount calculator to find a sale price or reverse a discount. Stack offers in order, add unit cost to check remaining margin, and compare discount sensitivity.

Free, no sign-up. Runs in your browser, with no AI calls.

Apply each discount to the price left by the previous step. A percentage multiplies that price by one minus the percentage divided by one hundred; a fixed discount subtracts an amount. With a unit cost, compare gross profit per sale before and after the discount to estimate the extra sales needed.

Your figures

The filled values are an editable example. Results update as you type.

Currency changes the units shown. No exchange-rate conversion is applied.

Discounts in order

Use prices and unit costs for the same item. Leave unit cost empty to calculate only the discount.

Your calculation

Sale price
$80
Sale price = $100 × (1 - 20 / 100)
Amount saved
$20
Saved = original price - sale price = $100 - $80
Effective discount
20%
Effective discount = saved / original price × 100
Gross profit per sale
$20
Gross profit = sale price - unit cost = $80 - $60
Margin after discount
25%
Margin = (sale price - unit cost) / sale price × 100
Extra sales needed
100%
Extra sales = ((original price - cost) / (sale price - cost) - 1) × 100

For every 100 original sales, the required discounted volume is 200. Round the final quantity up when planning whole units.

Equivalent total discount sensitivity, original price and unit cost stay fixed
DiscountSale priceGross profit per saleMargin after discount
0%$100$4040%
10%$90$3033.33%
20%$80$2025%
30%$70$1014.29%
40%$60$00%

Change one input at a time. Other entered amounts stay fixed. These scenarios do not predict demand or future returns.

For a percentage discount, multiply the remaining price by one minus the discount as a decimal. For a fixed discount, subtract the amount from the remaining price. Sales volume assumes unchanged unit costs and does not predict demand.

How to use this tool

Apply each discount in order
Percentage discount: next price = current price × (1 - discount / 100). Fixed discount: next price = current price - amount. Two discounts of 20% and 10% on 100 give 72, a saving of 28%, rather than 30%.
Check unit gross profit
Gross profit = sale price - unit cost. Margin = gross profit / sale price × 100. Use prices and costs for the same item. Include variable costs you want to cover. A zero sale price has no defined percentage margin.
Compare sales volume
Extra sales percentage = ((original price - unit cost) / (sale price - unit cost) - 1) × 100. A price of 100, cost of 60 and 20% discount leaves 20 profit instead of 40: you need 100% more sales. The calculation assumes the same unit cost and mix, with no additional fixed costs.

Discount formula source, checked 2026-10-12

Questions before you start

Two percentage discounts can be reversed without changing the result. A fixed amount and a percentage generally cannot: 20% then 10 off a price of 100 gives 70; 10 off then 20% gives 72. Each step is applied to the remaining price.

No. When the discounted gross profit is zero or negative, no finite increase in sales preserves a positive original gross profit. The calculator says so. It also withholds the comparison when the original gross profit is zero or negative.

No. Gross profit excludes fixed overhead and costs you did not enter. The sales uplift is the volume required by the arithmetic, not a forecast that customers will buy more. Check stock, capacity, acquisition costs and the promotion rules before making a decision.

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