Restaurant Cost Control: How to Work Out Your True Food Cost in 5 Minutes
Food cost is often treated as a monthly finance task. It should not be.
For an independent restaurant, a five-minute check on one dish can show whether your menu price, portion and supplier cost are still working. It can also reveal why sales are growing while cash is not.
The first number to check is simple:
Are you calculating food cost from the price the customer pays, or from the money your restaurant actually keeps?
If a dish sells for £12 including VAT, the net sale at the standard 20% VAT rate is £10. A £3 ingredient cost is therefore 30% food cost, not 25%.
That single mistake can understate food cost by five percentage points. On a dish with a higher cost, the difference can be six points or more. Across a menu, that quietly reduces your gross profit.
This matters more in September 2026. Food inflation is heading towards 9% in some industry warnings, with proteins, cooking oils, dairy and imported ingredients moving faster than the headline figure. The Food and Drink Federation’s latest forecast and warning shows why yesterday’s recipe card may no longer reflect today’s margin.
Labour is another pressure point. The National Living Wage is now £12.71 per hour. But this guide stays focused on food cost.
Here is a practical five-minute routine you can use on Monday.
1. Start with one dish
Do not begin by costing the whole menu.
Choose your best seller. It may be the dish that appears on almost every table, the one your team recommends most often, or the item that drives the most takeaway orders.
Popularity does not guarantee profitability. A dish can sell well and still damage your margin if its portion has drifted, its ingredients have increased in price, or its recipe includes more extras than you have costed.
Start with one dish. Find the friction. Then work through the rest of the menu.
2. Strip VAT from the selling price
Take the menu price customers see and convert it to the net selling price.
For a standard-rated dish at 20% VAT:
Net selling price = menu price including VAT ÷ 1.2
For a £12 dish:
£12 ÷ 1.2 = £10 net selling price
Do not simply subtract 20% from £12. That gives £9.60, which is incorrect. VAT is calculated as a proportion of the net price, so the correct method is to divide by 1.2.
This is the point where many menu calculations go wrong. Owners look at the £12 on the menu, then divide the £3 ingredient cost by £12:
£3 ÷ £12 = 25%
That makes the dish appear healthier than it is.
The correct calculation is:
£3 ÷ £10 = 30%
VAT is collected from the customer and paid to HMRC. It is not restaurant revenue.
Price from the net figure. Not the headline figure.
If your dish has a different VAT treatment, check the correct rate before calculating. The example above is for a standard-rated sale at 20%.
3. Cost the whole plate from current invoices
Now calculate what the dish actually costs to produce.
Use the latest supplier invoices rather than memory. Rice, oil and protein prices move. So do dairy, imported ingredients, packaging and small items that are easy to overlook.
Include:
- Main protein or primary ingredient
- Rice, noodles, chips, bread or other sides
- Cooking oil
- Sauce and stock
- Garnish and herbs
- Butter, dairy or finishing ingredients
- Disposable packaging for takeaway and delivery
- Any included dip, condiment or small extra
A dish that looks like a £3 plate may cost £3.30 once the oil, garnish, sauce and packaging are included.
That difference matters.
Account for yield and trim
What you buy is not always what you sell.
A whole chicken may include bones and trim. Vegetables lose weight when peeled. Meat can lose moisture during cooking. Frozen products may lose weight during defrosting.
If you buy 5kg of an ingredient but only have 4kg of usable product, your cost must be based on the 4kg, not the purchase weight.
The same applies to preparation losses. If a protein is trimmed before portioning, include that loss in the portion cost.
The calculation does not need to be complicated. Weigh the delivered product, weigh the usable product, and use the usable yield when working out the cost per portion.
Check the portion, not just the recipe
Portion drift is one of the quietest causes of food cost problems.
One chef uses 180g. Another uses 220g. A busy service adds an extra spoonful of sauce. A garnish becomes more generous over time.
The recipe card may still say the correct amount. The plate may not.
Add a 15-second weighing check for your three biggest-selling proteins once a week. It is a small routine, but it shows whether the written recipe is being followed in service.
Recipe cards must be used by the kitchen, not held in one chef’s head. Knowledge that exists in one person’s memory leaves when they do.
4. Divide ingredient cost by net selling price
Once you have the true portion cost, use this formula:
Food cost % = ingredient cost per portion ÷ net selling price × 100
Using the example:
- Menu price including VAT: £12
- Net selling price: £10
- Full ingredient and packaging cost: £3
£3 ÷ £10 × 100 = 30% food cost
The dish is therefore running at 30% food cost before considering labour, rent, energy, rates and other operating costs.
That is the number you need for menu decisions.
5. Compare the result with a sensible target
A common food cost target for many restaurants is between 28% and 32%.
That is a guide, not a rule. Your target depends on your concept, service style, menu mix, rent, labour model, pricing and sales channels. A premium tasting menu and a high-volume takeaway operation will not have the same cost structure.
The important point is that you choose a target deliberately and review against it consistently.
If your dish is at 30%, it may be working.
If it is at 38%, you have a decision to make:
Reprice the dish
A higher price may be appropriate if the customer value and market position support it.Re-portion the dish
Check whether the serving is larger than the recipe requires.Re-engineer the dish
Change an ingredient, simplify the garnish, adjust the side or redesign the preparation.Renegotiate or replace the ingredient
Ask suppliers for an alternative specification, compare quotes or review the buying frequency.
Do not make the decision from the food cost percentage alone. Check sales volume, customer expectations and the role of the dish on the menu.
But do not ignore the number either.
Look beyond the best seller
Once you have checked one dish, review the menu using two measures:
- How often does the dish sell?
- How much gross profit does it contribute?
This is the practical side of menu engineering.
- Stars: popular and profitable. Protect their quality and visibility.
- Plough horses: popular but lower margin. Review portions, price and supplier costs.
- Puzzles: profitable but not selling enough. Improve the description, positioning or staff recommendation.
- Dogs: low sales and low margin. Consider removing or redesigning them.
The popular dish may be the one destroying margin because it sells often. A small improvement on a high-volume item can be more useful than a large improvement on a dish that sells twice a week.
Sales show what customers choose. Costing shows whether that choice works for you.
Use one bin audit to find waste
You do not need a month of guessing to understand waste.
Carry out one bin audit during a normal week. Look at what is being thrown away and record the reason:
- Overproduction
- Spoilage
- Preparation trim
- Incorrect orders
- Returned plates
- Expired stock
- Damaged packaging
A bin audit often reveals that the problem is not one dramatic loss. It is repeated small losses: too much rice cooked, vegetables prepared too early, sauce discarded at the end of service, or protein portions cut inconsistently.
Measure what is being discarded. Then decide whether the answer is better forecasting, smaller batch preparation, improved storage or a change to the recipe.
Keep supplier checks routine
Food cost control is not only a kitchen task.
Each month:
- Review your top 10 ingredient lines.
- Compare at least two supplier quotes.
- Question every unexpected price increase.
- Check that the quantity delivered matches the invoice.
- Check that the specification delivered matches what you ordered.
- Record price changes on the recipe card or costing sheet.
You do not need to challenge every penny. You do need to know where the changes are coming from.
A supplier increase may be justified. It may also be an old price that was never queried, a changed pack size, or a substitution that costs more than the original product.
Good restaurant operations management is often this practical. Check the invoice. Weigh the portion. Review the waste.
Make the five-minute check a weekly habit
The calculation is quick. The value comes from repeating it.
Each week, choose one dish and ask:
- What is the current net selling price?
- What does the full plate cost today?
- Is the portion still being served consistently?
- Is the dish within the agreed target?
- What is the next decision?
Keep a simple record. Over time, you will see which ingredients move, which dishes drift and where your menu needs attention.
This is a useful starting point for Restaurant Profitability: 7 Mistakes Independent Owners Are Making in 2026 (and How to Fix Them). Food cost is one part of profitability, but it is often one of the clearest places to begin.
Independent restaurants are operating under sustained pressure. Industry figures indicate that 52% of UK hospitality leaders are reporting falling profitability, while critical distress across hospitality is up 17.5% year on year. More than 800 hospitality businesses are also backing calls for a VAT cut.
Those wider pressures are real. But you still need to make decisions at plate level.
Start with the dish customers order most. Strip out VAT. Use current invoices. Weigh the portion. Check the waste.
Clear numbers lead to calmer decisions.
If you want a second view of your menu, supplier costs or restaurant operations, Yin Fei Consulting’s services can provide a practical starting point. A useful conversation, not a sales script.