A little clarity for your next decision
Discount profitability calculator
See how a discount changes profit per unit and the extra sales volume needed to match your original total profit.
Plan your discount
Example values loaded. Change any number to make it yours.
Formatting only. Changing currency does not convert amounts.
How many units you would sell at full price. Use at least 1 to compare volume; the example uses 100.
Extra costs & fees (optional)
Amounts are per unit, with one unit per transaction. The percentage fee applies to the selling price after discount. Blank optional fields count as zero.
Your shipping cost after any amount covered by the buyer.
Boxes, labels, and other packaging.
Additional costs attributable to one unit.
Applied to the selling price. Blank means zero.
Assumes one unit per transaction.
The real cost of your discount
Discounted selling price
$40.00
Per unit, before tax.
Profit before discount
$20.00
Per unit, after all entered costs and fees.
Profit after discount
$10.00
Per unit, after all entered costs and fees.
Margin before discount
40%
Profit after costs ÷ original price.
Margin after discount
25%
Profit after costs ÷ discounted price.
Profit reduction
50%
Percentage of your original per-unit profit lost.
Original total profit
$2,000.00
At your baseline of 100 units.
Both bars use the same scale. Losses extend to the left of zero.
Sales needed to match your profit
At a 20% discount, profit per unit changes from $20.00 to $10.00. To match your original $2,000.00 profit, you need 200 total units: 100 more (100% more sales).
Required units
200
Rounded up to a whole unit to match the original total profit.
Additional units
100
Extra units above your full-price baseline.
Sales volume increase
100%
Based on the rounded-up required units.
This is a profit comparison, not a sales forecast. It assumes unchanged per-unit costs and one unit per transaction. Excludes tax, returns, and unentered costs. Displayed amounts are rounded.
Results updated. Discounted price $40.00. Profit after discount $10.00 per unit.
How the calculation works
Compare profit after the variable costs and fees you enter. Product cost and per-unit costs stay the same; percentage payment fees are recalculated against each selling price.
- Discounted price = original price × (1 − discount percentage ÷ 100)
- Profit per unit = selling price − product cost − per-unit costs − percentage fee − fixed fee
- Margin = profit per unit ÷ selling price × 100
- Profit reduction = (original unit profit − discounted unit profit) ÷ original unit profit × 100
Required units = round up (original unit profit × baseline units ÷ discounted unit profit)
Additional units = required units − baseline units. Volume increase = additional units ÷ baseline units × 100. This comparison requires positive original and discounted unit profit and a positive baseline volume.
This is a volume target, not a prediction of demand. We assume one unit per transaction, unchanged variable costs, and no extra overhead. Price calculations keep their precision until display; actual checkout rounding, tax, and fee rules can differ.
A worked example
A USD 50 item with USD 30 product cost earns USD 20 per unit before any optional costs. Selling 100 units produces USD 2,000 profit.
A 20% discount lowers the price to USD 40 and profit to USD 10 per unit. Margin falls from 40% to 25%; unit profit falls by 50%.
You would need 200 units to match the original USD 2,000 profit: 100 additional units, or a 100% increase in sales volume.
A few common questions
What if the discounted price loses money?
If discounted profit per unit is zero or negative, selling more cannot match a positive original profit. Required and additional units are unavailable, with an explanation. The calculator still shows the loss or zero profit.
What if the original product already loses money?
There is no meaningful positive profit target to recover. The calculator shows both unit-profit results but does not present a misleading sales-volume break-even figure or percentage profit reduction from a non-positive base.
Why are required units rounded up?
You generally sell whole units. If the calculation needs 133.33 units, 133 would fall short, so the tool requires 134. The percentage sales-volume increase uses that rounded-up count.
Does this apply a Shopify discount?
No. This independent calculator only models the numbers you enter. It does not connect to Shopify, change prices, or create a discount. The related PriceWrench page describes the app separately; it remains in development.