Guide · costs

Restaurant GP and food cost: costing a dish from recipe to plate

Most menus are priced by feel and checked by the accountant months later. Costing a dish properly takes an afternoon and a spreadsheet: the weight of everything on the plate, the price from the last invoice, and one honest number for what is lost on the way. This guide walks through it with a plate of fish and chips.

Published 24 October 2026 · General information for UK and Irish restaurants, not tax advice.

GP and food cost percentage: two views of one plate

Food cost percentage is what the ingredients cost as a share of what the dish sells for. Gross profit, or GP, is the rest: the share left to pay for wages, rent, energy and, eventually, you. They always add up to one hundred, so a dish with a food cost of 28% runs at a GP of 72%.

The trap is VAT. In the UK, food eaten on your premises is a supply in the course of catering and is standard-rated, and the standard rate is 20%. The price on the menu therefore includes VAT that is not yours. Divide the menu price by 1.2 before you work out anything; a dish that seems to run at 75% on the menu price is nearer 70% on the price you actually keep. Irish restaurants divide by their own rate, which for food moved to 9% in July 2026.

The formula, written once: GP% = (net price − plate cost) ÷ net price × 100. Turned round to set a price from a target: net price = plate cost ÷ (1 − target GP), then add VAT for the menu.

Costing a recipe, with its sizes and options

Weigh the plate, not the recipe card
Cook the dish the way the line cooks it on a Friday and weigh each component as it goes on the plate. The recipe card says 200 g of chips; the cook's scoop may say 260.
Take the price from the last invoice
Divide the pack price by the pack weight to get a cost per gram, millilitre or piece. Use the delivered price, not the list price, and update it when the invoice changes.
Allow for yield
A whole fish, a sack of potatoes or a case of lemons loses weight before it reaches the plate. If 1,000 g of potatoes give 700 g of chips, the yield is 70%, and every gram of chips costs 1 ÷ 0.7 of a gram of potato.
Cost every size and every option
A small and a large portion are two recipes. So is the extra side or the vegan swap. An option that adds a cost and no price is a discount nobody decided on.

Waste and counts: the cost the recipe cannot see

A costed recipe is what the dish should cost. The kitchen's real cost includes what was dropped, burnt, over-portioned, eaten by staff or thrown out at the end of the week. Write waste down when it happens, by item and weight, with a one-word reason. A kitchen that records its waste for a month usually finds one or two items that explain most of it.

Counts are the other half. Count the same items, at the same time of day, on the same day each week or month. A count taken before a delivery one month and after it the next is two different kitchens.

Variance between two counts

Variance is the gap between what you should have used and what you did. What you used is the opening count, plus deliveries, minus the closing count. What you should have used is every dish sold multiplied by its recipe. The number of each dish sold comes from your till's sales report, or from Slotora's own sales report when the orders run through Slotora. If the two differ by more than the waste you wrote down, the difference is portioning, a recipe that is out of date, an invoice entered wrongly, or stock leaving by the back door.

Slotora does this arithmetic as the kitchen works. Each dish, size and option has its recipe, so the stock on hand follows what was sent to the kitchen; counts, deliveries and waste are entered on a tablet; the food cost per portion is shown beside the dish; and the variance between two counts is a screen, not a weekend with a calculator. Suggested orders fill up to the par level you set; you copy the purchase order as text, send it to your supplier yourself, and receive the delivery at the invoice price.

A worked example: fish and chips

The weights are a typical portion and the prices typical of a UK wholesale invoice this autumn. Yours will differ, and that difference is the point of costing.

Example

One portion of fish and chips, costed line by line

Fish and chips: what is on the plate and what it costs (example prices)
Component	On the plate	Line cost
Cod fillet	200 g, skinned and boned, at £17.00 a kilo	£3.40
Chips	250 g cooked, from 360 g of potato at 70p a kilo (70% yield)	£0.25
Batter	60 g flour and 90 ml beer	£0.27
Frying oil	an allowance per portion, from how often the fryer is changed	£0.25
Mushy peas	100 g at £2.00 a kilo	£0.20
Tartare sauce and lemon	30 g sauce, one wedge	£0.25

The plate costs £4.62. On the menu at £16.95, the net price after 20% VAT is £14.13, so the food cost is 33% and the GP 67%.

For a GP of 70%, the net price has to be £4.62 ÷ 0.30 = £15.40, which is £18.48 on the menu: call it £18.50. Or keep £16.95 and cut the fillet to 180 g: that saves 34p, the plate costs £4.28, and the GP is just under 70%.

Notice that the fish decides almost three quarters of the answer: 20 g more fillet costs more than all the peas.

A free costing sheet to download

Eight columns in any spreadsheet are enough: one row per ingredient, one tab per dish, and one tab for the prices from your invoices, so a price is changed once. The sheet below opens in Excel, Numbers or any other spreadsheet, with the cod line of the example already filled in.

Ingredient
Pack size
Pack price (last invoice)
Unit
Cost per unit
Quantity on the plate
Yield %
Line cost

Line cost is cost per unit × quantity ÷ yield, and the lines add up to the plate cost. Below them: the menu price, the net price (÷ 1.2 in the UK), food cost % and GP %.

Download the costing sheet (CSV)Hear when Slotora opens

GP and food cost: short answers

How do I calculate GP on a dish?

Take the menu price, remove VAT to get the net price, subtract the plate cost, and divide the result by the net price. Multiply by 100 for a percentage.

What is the difference between food cost and GP?

Food cost percentage is the ingredients as a share of the net price; GP is what is left. The two always add up to 100%.

Does Slotora order from my suppliers?

It suggests what to order up to your par levels and keeps the purchase order from draft to received; you send it to the supplier yourself.

Sources for the VAT in this guide (checked 24 October 2026)

Stock and recipe costing in Slotora · The menu, sizes and options · Pricing

Irish restaurant VAT at 9% · All guides