Why a small discount hurts so much
The trap is that a discount comes out of your profit, not your costs. Your costs don’t move when you drop the price — so every dollar of discount is a dollar off the bottom line.
How discounts affect profit margin
A discount looks small on the price tag but lands entirely on your profit. Here’s the maths behind the “discount trap” — and the volume you’d need to sell to break even.
The break-even sales table
This is the extra unit volume you need just to maintainthe same profit after a discount, for three starting margins. The formula is: extra volume = discount ÷ (margin − discount).
| Discount | 30% margin | 40% margin | 50% margin |
|---|---|---|---|
| 5% | +20% | +14% | +11% |
| 10% | +50% | +33% | +25% |
| 15% | +100% | +60% | +43% |
| 20% | +200% | +100% | +67% |
| 25% | +500% | +167% | +100% |
Read it like this: on a 30% margin, a 15% discount means you must sell 100% more— double the units — to earn the same profit. A blank column would appear once the discount exceeds the margin, because at that point you’re selling at a loss no matter the volume.
When discounting still makes sense
- Clearing dead stock whose cost is already sunk.
- Winning a first order from a customer who’ll buy again.
- When the discount genuinely drives volume above the break-even bar in the table.
- As a value-add instead — a free gift or free shipping often protects margin better than a straight price cut, and lifts average order value.
Check before you cut
Before you post a sale, run the discounted price through the profit margin calculator to see the margin you’ll actually be left with. If you’re fuzzy on how the percentages work, start with margin vs markup.
Pricing & margin guides
How to Calculate Profit Margin
The profit margin formula explained with step-by-step worked examples.
Margin vs Markup
Why they're not the same, the formulas for each, and a conversion table.
How to Price a Product
A step-by-step pricing method that protects your margin from day one.
What Is a Good Profit Margin?
Healthy margin benchmarks by industry and how to know where you stand.
How to Calculate Break-Even Point
The break-even formula, contribution margin, and how many units you must sell.
Cost of Goods Sold (COGS)
What counts as COGS, what doesn't, and the formula to calculate it.
Gross Profit vs Net Profit
The difference between the two, with a worked income-statement example.
Average Order Value (AOV)
The AOV formula, why it matters, and proven ways to increase it.
Contribution Margin
What contribution margin is, the formula, and how it drives break-even.
Fixed vs Variable Costs
The difference, why it matters for pricing, and how to classify your costs.
Keystone Pricing
The classic 2x markup rule — what it is, the margin it gives, and when to use it.
Retail vs Wholesale Pricing
How to price for both channels without eroding your retail margin.
How to Calculate ROI
The return on investment formula with worked examples for stock and ads.
How to Increase Profit Margin
Ten practical, tested ways to widen your margin without losing sales.
More free calculators
Profit Margin Calculator
Sale price, margin, markup, or cost — four modes for any scenario.
Etsy Profit Calculator
Net profit after Etsy listing, transaction, payment, and Offsite Ads fees.
Amazon FBA Profit Calculator
Net profit, margin and ROI after Amazon referral, fulfillment and storage fees.
eBay Profit Calculator
Net payout after eBay's final value fee, per-order charge and international fees.
Shopify Profit Calculator
Real profit per sale after Shopify payment processing, surcharges and plan share.
Frequently asked questions
How much does a discount reduce profit?
Far more than the discount percentage suggests, because the discount comes entirely out of your profit, not your costs. On a product with a 40% margin, a 20% discount cuts your profit in half — you'd need to double your unit sales just to make the same total profit.
How do I calculate the new margin after a discount?
Subtract the discount from the sale price to get the new price, then recalculate: new margin = (new price − cost) ÷ new price. A $50 item costing $30 has a 40% margin; a 20% discount drops the price to $40 and the margin to (40 − 30) ÷ 40 = 25%.
How much extra do I need to sell to break even on a discount?
Required volume increase = discount ÷ (original margin − discount), using decimals. For a 40% margin and a 20% discount: 0.20 ÷ (0.40 − 0.20) = 1.0, meaning you must sell 100% more units — double the volume — just to match your previous profit.
Are discounts ever worth it?
Yes, when they drive enough extra volume, clear dead stock, win a first purchase from a lifetime customer, or move a product whose costs are already sunk. The key is to run the numbers first so you know the volume bar you have to clear.
What's a better alternative to discounting?
Adding value (bundles, free gifts, free shipping thresholds) often lifts sales while protecting margin better than a straight price cut, because you control the cost of what you give away. Raising average order value is usually more profitable than discounting.