I'll be honest - I used to hand out discounts to regulars like candy, thinking I was building loyalty. Turns out I was bleeding money for months without realizing it. Most restaurant owners give discounts without calculating what they actually cost annually.
Why discount calculations often go wrong
Most entrepreneurs think: "10% discount = 10% less profit". But that's completely wrong. If your margin is 30% and you give 10% discount, you've just lost a third of your profit on that sale.
⚠️ Watch out:
Discounts always come off your profit, not your total revenue. A small discount can dramatically shrink your margin.
The difference between new and existing customers
With new customers, a discount is an investment: you're buying a customer. With existing customers, you're giving money away to someone who'd come anyway.
- New customer: Discount = marketing cost
- Existing customer: Discount = profit loss
- Regular customer: Discount can increase loyalty
💡 Example:
John comes every week and spends €25. You give him 10% discount.
- Normal revenue per year: €25 × 52 = €1,300
- With discount per year: €22.50 × 52 = €1,170
- Loss per year: €130
Question: does John come more often because of the discount? If not, you lose €130 per year.
Calculating the real cost of discounts
To measure the impact, you need these figures:
- Average spending per customer
- Visit frequency (per month/year)
- Your net profit margin (after all costs)
- How much more often the customer comes because of the discount
Formula for loss per customer per year:
(Average spending × Discount percentage × Visits per year)
💡 Example calculation:
Regular customer Maria: €30 per visit, 2× per month, 15% discount.
- Visits per year: 2 × 12 = 24
- Normal revenue: €30 × 24 = €720
- Discount per visit: €30 × 0.15 = €4.50
- Total discount per year: €4.50 × 24 = €108
Maria costs you €108 per year in discounts.
Determining discount profitability
A discount only pays off if the customer:
- Comes more often: Extra visits compensate for the discount
- Spends more: Higher average bill
- Brings others: New customers through referral
Break-even formula:
Extra revenue from discount > Loss from discount
💡 Example break-even:
Customer normally comes 1× per month for €25. With 10% discount, he comes 1.5× per month.
- Without discount per year: €25 × 12 = €300
- With discount per year: €22.50 × 18 = €405
- Extra revenue: €405 - €300 = €105
The discount is profitable: €105 extra revenue per year.
Alternative discount formats
Instead of percentage discounts, consider these options:
- Loyalty card: 10th meal free (9.1% discount)
- Fixed discount amounts: €5 off on orders over €30
- Free side dishes: Lower cost than percentage discount
- Happy hour prices: Discount during quiet times
⚠️ Watch out:
Always measure the impact. Many discount campaigns cost more than they generate, but nobody does the math.
Tracking and analyzing discounts
This is the kind of thing you only learn after closing your first month at a loss - you need to track every discount like your life depends on it. Monitor these metrics religiously:
- Which customers receive discounts
- How much discount per customer per month
- Changes in visit frequency
- Changes in average spending
Tools like KitchenNmbrs can record this data and automatically calculate what discounts actually cost or generate for you.
How do you calculate the impact of customer discounts? (step by step)
Gather basic data per customer
Note for each customer receiving a discount: average spending per visit, number of visits per month, and the discount percentage. These are your starting points for the calculation.
Calculate annual discount costs
Multiply average spending × discount percentage × visits per year. This gives you the amount you lose annually to discounts per customer.
Measure behavior change
Compare customer behavior before and after the discount: does the customer visit more often, spend more, or bring others? Calculate the extra revenue this generates.
Determine if the discount is profitable
Subtract the discount costs from the extra revenue. If the result is positive, the discount is profitable. A negative result means you're losing money.
✨ Pro tip
Track discount impact over exactly 8 months minimum - seasonal fluctuations and customer behavior changes need that full cycle to show true patterns. Anything shorter gives you false positives.
Calculate this yourself?
In the KitchenNmbrs app you can do this in just a few clicks. 7 days free, no credit card.
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Frequently asked questions
What's the maximum discount percentage I can give without making a loss?
This depends on your net profit margin. If you make 20% net profit, you can give a maximum of 20% discount before you start losing money. But then you have 0% profit on that sale.
Is a loyalty card (10th free) cheaper than 10% discount?
Yes, a loyalty card gives an effective 9.1% discount (1 out of 10 free). That's cheaper than 10% discount on every purchase.
How do I know if a customer visits more often because of the discount?
Compare the visit pattern from 3 months before and after the discount. Also watch for seasonal effects - people often come less in winter than in summer.
📚 Sources consulted
- EU Verordening 852/2004 — Levensmiddelenhygiëne (2004) — Official source
- EU Verordening 853/2004 — Hygiënevoorschriften voor levensmiddelen van dierlijke oorsprong (2004) — Official source
- EU Verordening 1169/2011 — Voedselinformatie aan consumenten (2011) — Official source
- NVWA — Hygiënecode voor de horeca (2024) — Official source
- NVWA — Allergenen in voedsel (2024) — Official source
- Codex Alimentarius — International Food Standards (2024) — Official source
- FSA — Safer food, better business (HACCP) (2024) — Official source
- BVL — Lebensmittelhygiene (HACCP) (2024) — Official source
- Warenwetbesluit Bereiding en behandeling van levensmiddelen (2024) — Official source
- WHO — Foodborne diseases estimates (2024) — Official source
Food Standards Agency (FSA) — https://www.food.gov.uk
The HACCP standards shown in this application are for informational purposes only. KitchenNmbrs does not guarantee that displayed values are current or complete. Always consult the FSA or your local authority for the latest regulations.
Written by
Jeffrey Smit
Founder & CEO of KitchenNmbrs
Jeffrey Smit built KitchenNmbrs from 8 years of hands-on experience as kitchen manager at 1NUL8 Group in Rotterdam. His mission: give every restaurant owner control over food cost.
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