Plate cost: the arithmetic behind a single dish

Plate cost is what everything on one plate costs the kitchen to buy: the protein, the sides, the sauce, the garnish, the butter it was basted in and the oil it was fried in. It is the number underneath every menu price and every food cost percentage, and it is also the number most kitchens get slightly wrong, because the obvious ingredients are costed carefully and the small ones are left out.

The small ones add up. A lemon wedge, a few grams of herbs, a spoonful of sauce made from a batch nobody costed, the oil in the pan: on their own each is a few pence or cents, and together they can add ten per cent or more to the cost of a dish. A price set from an incomplete plate cost leaves less margin than the kitchen believes, on every plate it sells.

This guide works through the arithmetic step by step, from the price on the supplier's invoice to the cost of the finished plate, with one dish costed in full. It then shows what the result means for the price. Every figure in it is an example; use your own invoices and your own recipes.

Three terms are used for closely related things, and it helps to separate them.

A recipe cost is the cost of a batch: everything that goes into a pot of sauce, a tray of potatoes or a kilogram of dough. A cost per portion is that batch cost divided by the number of portions it makes. A plate cost adds up every portion on one plate: the main item, the sides, the sauce and the garnish, plus anything else the plate carries.

Most kitchens need all three. The batch costs feed the portion costs, and the portion costs feed the plate. Our guide to recipe costing covers the batch side in detail. This guide focuses on assembling the plate and on the items that get missed.

A good plate cost sheet lists every component of the dish as it is served, with five figures for each:

The last column, added up, is the plate cost. Everything that makes the sheet accurate happens in the first three columns.

Start from the invoice, not the price list. Use the price per kilogram, litre or unit that you actually paid, after any discounts, and net of VAT if your business reclaims it. If the supplier charges for delivery and the charge is significant, decide whether to spread it across the ingredients or treat it as an overhead, and do the same for every dish.

Watch the units. A case of 6 tins, a 2.5 kilogram tin, a box sold by count and a box sold by weight all need converting to a common unit before they can be compared. Most costing errors are unit errors.

Use the latest price, not an average from months ago. Plate cost is useful precisely because it moves when prices move.

What you buy is not what you serve. A whole fish loses its head, bones and skin; a beef rib loses fat and sinew; vegetables lose peel, stalks and outer leaves. The usable share is the yield, and the cost of the usable part is the purchase price divided by the yield.

An example. Whole sea bass bought at 15.00 a kilogram, filleted, yields 45 per cent of its weight as skin-on fillet. The cost of the fillet is therefore 15.00 divided by 0.45, which is 33.33 a kilogram. A kitchen that costs its fillet at 15.00 a kilogram is out by more than a factor of two.

Measure yields yourself, by weighing before and after preparation, and do it more than once, because yields vary with the size and quality of what arrives and with who is doing the preparing. Write the yield on the costing sheet, so the next person can see where the number came from.

Many ingredients lose weight in cooking. Meat and fish lose water; vegetables lose water; braises reduce. If the portion is defined by its cooked weight, the raw quantity needed is larger, and the cost must be worked out from the raw quantity.

An example. A beef dish is served as 150 grams of cooked meat. If the cut loses 25 per cent of its weight in cooking, each portion needs 200 grams of trimmed raw meat. Cost it at 200 grams, not 150.

Decide, for each component, whether its portion is defined raw or cooked, and keep to it. The specification the chefs work to should use the same definition, or the costing and the cooking will quietly disagree.

Sauces, stocks, dressings, purées, pickles and doughs are made in batches and used across several dishes. Cost each batch as its own recipe, divide by what it yields, and carry the cost per gram, millilitre or portion into every dish that uses it.

Measure the yield of the finished batch, not the sum of its ingredients. A reduction that starts with two litres of liquid and ends with 700 millilitres has a yield of 700 millilitres, and the cost of the whole batch sits on those 700. Costing it on the starting volume understates it nearly threefold.

Keep sub-recipe costs on their own sheet, linked to the dishes that use them, so that a change in the price of butter updates every sauce, and every sauce updates every plate.

Garnish is where plate costs are most often incomplete. It feels too small to cost, and it is often added at the pass by whoever is plating, so it never appears in the written recipe.

Cost it anyway. A lemon wedge is an eighth of a lemon. A pinch of herbs is a few grams of something that may cost 30 or 40 a kilogram once picked and trimmed. A swirl of good oil, a few flakes of salt, a dusting of something on a dessert, a sprig of something green on the side: each is small, and each is on every plate. Weigh what the team actually uses for a few services, write it into the specification, and add it to the cost.

Cooking fats are easy to forget because they are not on the plate in an obvious way. They should still be costed.

For pan-frying and basting, measure the oil or butter used per portion and cost it like any ingredient. For deep-frying, estimate the cost per portion from how much oil the fryer uses. An example: a fryer holds 20 litres, the oil costs 1.50 a litre, and it is changed once a week with some topping up in between, for a total of about 36 a week. If the fryer cooks 900 portions a week, the oil costs about 4 pence or cents a portion. That is small, but it belongs on every fried plate, and it rises sharply when the oil is changed more often or the fryer is underused.

Some items are served per table or per guest rather than per dish: bread and butter, an amuse-bouche, olives, petits fours, the condiments on the table. They do not belong on any one dish's plate cost, but they are part of the cost of serving a guest.

Cost them per cover and keep them on their own line. When you look at the food cost of the whole menu, they need to be included; when you look at the margin on one dish, they should not distort it. A venue that gives every guest free bread and butter at an example 0.40 a cover is spending money on every cover, whatever is ordered.

However careful the costing, some cost escapes it: salt and pepper, the spoon of sauce used to taste, the portion re-plated after a slip, the trimmings that could not be used. Many kitchens add a small allowance to each plate cost to cover these, a few per cent of the costed total.

How large it should be is a decision for your kitchen, and it should be checked against reality: if the gap between your theoretical and actual food cost is persistently larger than the allowance, the allowance is too small or something else is going wrong. The allowance is a recognition that a costing is a model, not an excuse for leaving things out of it.

Pan-fried sea bass with crushed new potatoes, tenderstem broccoli and beurre blanc. All prices are invented for the example.

The costed components add up to 7.17. An allowance of 3 per cent adds 0.22, giving a plate cost of 7.39.

Notice where the money is. The fish is nearly three quarters of the cost, which is typical of protein-led dishes, and the yield on the fish is the single most important number on the sheet. But the sauce, garnish and oil together come to 0.63, nearly a tenth of the total, and a costing that left them out would have been wrong by that much on every plate.

Once the plate cost is known, the price follows from what the dish needs to earn. Continuing the example: the dish sells at 26.00 including VAT at an example 20 per cent, which is 21.67 before tax. The food cost percentage is 7.39 divided by 21.67, about 34 per cent. The gross profit per dish, the cash left after the food, is 21.67 minus 7.39, which is 14.28. Expressed as a share of the price, that is the dish's gross margin: about 66 per cent here.

Whether that is right depends on the rest of the menu and the venue. A percentage above the menu's average may be fine for a dish that leaves a large cash margin and sells well; a dish with a low percentage may still leave too little cash to be worth its place. Our guides to menu pricing methods and to gross profit on a dish cover the decision, and menu engineering shows how to combine the margin with each dish's popularity.

Always calculate the percentage on the price before tax. Including VAT or sales tax in the price makes every dish look cheaper to make than it is.

Many dishes are not one plate but several: a steak with a choice of sauce, a main with a choice of side, a burger with optional extras. Each version has its own plate cost, and the price usually stays the same.

Cost every version that is offered, not only the one in the photograph. Then look at two of them in particular: the version guests choose most often, which drives the dish's real food cost, and the most expensive version, which sets the floor for its margin. If the most expensive choice leaves too little margin at the menu price, either charge for it as an extra or change what is offered.

Paid extras deserve their own plate cost too. An extra portion of protein or a premium topping is often priced by habit rather than by cost, and the habit can be out of date by a long way.

A plate cost is correct on the day it is calculated. After that it drifts, as prices change and as the dish changes in the hands of the team.

Set a few triggers for re-costing:

Keep the costing in a spreadsheet or system where ingredient prices are entered once and flow into every sub-recipe and plate. A costing kept on paper, dish by dish, is rarely updated, because updating it means redoing every sheet that uses the ingredient that changed.

A plate cost assumes the plate is made to specification. If the kitchen serves 190 grams of fish rather than 160, the real plate cost of the example dish rises by about a fifth on the fish alone. Costing and portion control are two halves of the same job.

Three habits keep them together. Write a specification for every dish, with weights and a photograph of the finished plate. Keep scales at the stations where portions are set, and use them, especially for proteins and expensive garnishes. And check portions now and again during service, not to catch anyone out, but to see whether the specification still matches what the kitchen actually does. When it does not, change one or the other, and re-cost.

Drinks follow the same logic, with different names. The cost of what goes in the glass, including mixers, garnish and ice, divided by the price before tax, is the drink's pour cost. Our guide to pour cost works through a cocktail costed the same way as the plate above.

A plate cost needs your recipes, your yields and your invoice prices, and those stay in your own costing sheet today. servearound holds the other side of the sum: the dishes, their prices and what sells.

Each dish in menus carries its name, price, description, photograph and dietary and allergen information, and a change of price shows on the till and on every guest menu at once. The menu report in Analytics shows units sold and revenue for every dish over any range of dates, which tells you which plate costs matter most: the ones on the dishes that sell.

servearound does not hold recipe, ingredient or dish costs today, so the plate cost itself is worked out on your own sheet. If you would like to see the menu and sales side, get in touch.

It is the cost of everything on one plate as served: the main item, sides, sauce, garnish and cooking fats, worked out from what you pay for each ingredient, after trim and cooking losses.

Cost per portion is the cost of one portion of a single recipe, such as one portion of sauce. Plate cost adds up every portion on the plate.

Weigh it as it arrives, prepare it as the kitchen normally does, and weigh the usable part. Divide the second weight by the first. Repeat a few times, with different deliveries and different people, and use the typical result.

Yes. It is on every plate, and together with sauces and cooking fats it can be a meaningful share of the cost. Weigh what the team actually uses and write it into the specification.

Whenever a significant ingredient changes price, supplier or specification, and as a whole menu at least every few months. A plate cost that is a year old is a guess.

No. Divide the plate cost by the price before tax. Including tax makes the food cost look lower than it is.

There is no universal figure. Look at the food cost percentage and the cash gross profit together, against the rest of your menu and what the dish sells.

Units and yields. Converting case prices to unit prices wrongly, and costing whole fish or meat as if every gram were usable, cause larger errors than anything else.

Plate cost is the cost of everything on the plate: start from the price you actually paid, convert it to a common unit, divide by the usable yield after trim and cooking, and cost each component at the quantity the specification says. Cost sauces and other sub-recipes on their finished yield, and include the garnish, the cooking fats and a small allowance for what escapes the costing.

Then use it. Divide by the price before tax for the food cost percentage, subtract it from that price for the gross profit per dish, and set prices from both. Keep costs current when prices change, and keep portions matched to the specification, because a plate cost is only as true as the plate the kitchen actually serves.