Most menus are priced by feel. The chef knows the food cost, a rough "three times the ingredients" rule gets applied, and prices are rounded to something that looks right on the page. It works until it doesn't: margins quietly erode, a supplier invoice lands, and nobody can point at the dish that's leaking money. Contribution margin fixes that by giving every dish one honest number.
What contribution margin actually is
Contribution margin is the money a dish leaves over after its direct costs: selling price minus food, packaging and delivery fees. It's not profit — it's the contribution each sale makes towards your rent, wages, and everything else that doesn't change when one more plate leaves the pass.
The reason it matters: two dishes at the same price can leave wildly different contributions, and the busy ones deserve your attention first.
A worked example
Take a chicken burger priced at £14.50. Add up the bun, chicken, sauce, garnish, the box and napkin: roughly £4.35 in direct costs. The contribution margin is £10.15 per sale.
Now a soup of the day at £6.50, costing about £1.30 a bowl. It contributes £5.20 — half the burger's contribution from a dish that takes a fraction of the kitchen time, holds almost no waste risk, and sells consistently through winter.
Under the "three times cost" rule, both dishes look fine. Under contribution margin, the soup quietly outperforms dishes twice its price — and deserves a better spot on the menu than it usually gets.
Why the 3x rule lets you down
Food-cost multipliers treat all ingredients alike, but your costs don't behave alike. A truffle dish might carry a 60% food cost yet still contribute more per plate than a "safe" 30% dish that sells once a night. The multiplier also ignores the two things that actually sink margins: prep time hogging your wage bill, and waste on fresh items that don't sell through.
Contribution per minute: the number nobody tracks
A plated dessert that needs eight minutes of chef time at £15 might contribute £9 on paper while blocking the pass through your busiest hour. A grab-and-go brownie at £3.50 contributes £2.50 in ten seconds. On a Saturday night, the second option can earn the kitchen more per hour than the first — contribution per minute of kitchen time is worth a glance when you plan a menu, not just contribution per plate.
Menu engineering: a ten-minute check
Split your dishes into four groups using two questions: does it sell well, and does it contribute well?
- Stars (sell well, contribute well): protect them — don't touch the price, put them front and centre.
- Ploughhorses (sell well, contribute poorly): nudge the price up or trim the portion's cost without making the dish feel smaller.
- Puzzles (contribute well, sell poorly): reposition them — better description, better photo, a server recommendation.
- Dogs (neither): remove them. Every dog on the menu adds inventory, prep and menu clutter for nothing.
Practical steps this week
Plate-cost your ten best sellers first — they carry most of your revenue, so errors there cost the most. Set a minimum contribution per dish that reflects your real overheads (a useful rule of thumb: if your monthly fixed costs are £8,000 and you serve 3,000 covers, every dish needs to average £2.67 of contribution just to stand still). Then fix the dogs, nudge the ploughhorses, and leave the stars alone.
When you adjust prices, small and honest beats large and hidden: moving £12 to £12.50 rarely moves demand, and customers forgive a transparent price far sooner than a shrunken portion.
Keep prices honest as costs move
Supplier prices shift constantly, and a menu that's repriced twice a year guarantees months of quietly wrong margins. This is where format matters: a printed menu that needs a reprint every time a supplier invoice lands will always lag reality, while a digital menu takes the price change live in seconds — the same evening you spot the cost increase, before it's eaten a week of margin.
Revly helps restaurants and cafés run leaner with QR review systems, digital menus that update in seconds, and clean, fast websites — see the demo or get in touch.