Discount Impact Calculator
See how offering a discount affects your profit margins and how much more you need to sell to break even.
Fill in the fields above and click Calculate to see your results.
How to use
Enter your normal selling price, product cost, and the discount you are considering. The calculator shows your margin before and after the discount, and the key number most retailers never compute: how much more volume you must sell just to earn the same total profit.
The math is brutal because the discount comes entirely out of your margin, not the price. At a 40% margin, a 20% discount removes half your profit per unit — so you need to sell twice as many. Before launching a promotion, decide whether that volume lift is realistic; if not, consider bundles, gifts-with-purchase, or loyalty points, which protect margin better than straight price cuts.
How it's calculated
Original Margin %
New Margin % (After Discount)
Required Sales Volume Increase (%)
Volume increase needed to maintain same absolute profit
Examples
Seasonal sale, 20% off
- Cost of Goods Sold (COGS):300,000
- Original Price:500,000
- Discount Percentage (%):20
Result
- New Margin % (After Discount):25
- Original Margin %:40
- Required Sales Volume Increase (%):100
The 20% discount halves per-unit profit (200,000₫ → 100,000₫), so the store must sell exactly twice as many units to earn the same total profit. Unless last year's sale doubled volume, this promotion destroys profit.
Modest 10% promotion
- Cost of Goods Sold (COGS):60,000
- Original Price:100,000
- Discount Percentage (%):10
Result
- New Margin % (After Discount):33.33
- Original Margin %:40
- Required Sales Volume Increase (%):33.33
Even a "small" 10% discount at a 40% margin demands 33% more unit sales to break even. If a typical promotion lifts your volume 15–20%, this discount quietly loses money despite the busier store.
Industry Benchmarks
| Metric | Typical Range |
|---|---|
| Healthy retail gross margins run 40–55%. Below 30%, almost no straight discount can pay for itself. | 40–55 % |
| Typical promotions lift volume 15–35%. If the required increase exceeds that range, the discount will likely lose money — use bundles or gifts instead. | — |
Data source: NYU Stern Margin by Sector (2025); Retail pricing studies (McKinsey/Bain pricing research)
Frequently Asked Questions
Why is a 10% discount so impactful?
How do I calculate the break-even volume increase for a discount?
When does discounting actually make sense?
What are alternatives to a straight price discount?
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