The cost of a plate is the sum of everything on it, at the weights you actually serve: the protein, the sides, the sauces, the fryer oil, what goes on the table, and an allowance for what gets lost on the line. You build it on a card, ingredient by ingredient, with prices from your latest invoices. A burger that "costs $1.76 in beef" really costs $4.10 once the rest is added.
What goes into a plate
A plate is more than the main recipe. Check these six layers:
- The protein, at the price per usable kilo after trim, not per kilo bought.
- The sides: fries, slaw, salad, rice.
- Sauces and dressings: house sauce, mayo, gravy.
- Oil: what you cook with and the fryer, shared out per portion.
- Table extras: ketchup and mayo cups, bread, butter, lemon wedges.
- Waste of the line: portions that go out large, plates sent back, things dropped.
If you already have the recipe written up as a standard recipe card, the plate cost card is the same thing with prices next to it.
Step 1: the real cost of each ingredient
Use the price on your latest invoice, not the one you remember. Then turn it into a cost per usable kilo with your own yield:
Cost per usable kilo = price per kilo bought ÷ (kilos you keep from each kilo)
Weigh before and after. If potatoes cost $1.40 a kilo and peeling and cutting leaves you 800 g of fries per kilo, your usable kilo costs 1.40 ÷ 0.80 = $1.75. Someone else's potatoes and peeler will give a different number. For meat, potatoes or onions, the yield calculator gives you the real cost per usable kilo after trim and cooking loss.
Step 2: the weights you actually serve
Weigh three or four plates as they go out in a normal service, not the perfect plate from the photo. If the fries vary between 180 and 260 g depending on who is on the fryer, your cost varies too. Until you fix the portion, use the average of what you weighed. How to fix it is in the guide to portion control.
Step 3: fryer oil and table extras
Fryer oil is in no recipe and it adds up. Work it out like this:
Oil per portion = cost of each oil change ÷ portions fried in that oil
If you change 15 litres at $2.20 a litre ($33) and fry about 200 portions before the next change, each portion carries 33 ÷ 200 = $0.165, call it $0.17.
Table extras work the same way: what you spend on them in a week divided by the plates served that week.
Step 4: waste of the line
Even when you weigh everything, a service always loses something: the burger cooked to the wrong temperature, the extra handful of fries, the bun that tore. To find out how much, compare for one week what you should have used according to your cards with what you actually used. If the difference is 5%, add 5% to the card. It is your number; measure it and keep it current. How to keep that record is in tracking restaurant waste.
Worked example: a burger and fries
Prices from your latest invoices; yields measured by you.
| Item | Sum | Cost |
|---|---|---|
| Beef patty, 160 g | mince at $11.00 a kg: 0.16 × 11.00 | $1.76 |
| Cheese slice | from the pack | $0.28 |
| Brioche bun | from the case | $0.55 |
| Lettuce, tomato, onion, pickles | a prep batch ÷ burgers | $0.42 |
| House sauce, 20 g | a batch ÷ portions | $0.18 |
| Fries, 220 g | $1.40 a kg, you keep 800 g: 0.22 × 1.40 ÷ 0.80 | $0.39 |
| Fryer oil | $33 per change ÷ 200 portions | $0.17 |
| Salt and seasoning | per plate | $0.03 |
| Ketchup and mayo cups | a week's spend ÷ plates | $0.12 |
| Recipe total | $3.90 | |
| Line waste, 5% | 3.90 × 0.05 = 0.195 | $0.20 |
| Plate cost | $4.10 |
The beef is $1.76. Everything else adds up to $2.34, more than half the plate. If you were costing the patty and bun only, you were missing most of it.
Against the price. If the menu price is $15.00 before tax, food cost is 4.10 ÷ 15.00 = 27.3%.
If you want a different food cost. Say you decide this plate should sit at 25%. The price would be 4.10 ÷ 0.25 = $16.40. That 25% is your decision, based on what the plate has to leave you; how to choose it is in the guide to food cost percentage. The menu price calculator does this sum for you.
What moves the cost most
With the card built, you can see which change matters most:
- Beef up from $11.00 to $13.00 a kilo: 0.16 × 13.00 = $2.08, so $0.32 more per plate.
- Fries portion from 220 g to 180 g: 0.18 × 1.75 = $0.315, about $0.07 less per plate.
- Oil changed after 250 portions instead of 200, if it still fries clean: 33 ÷ 250 = $0.13, $0.04 less.
The protein leads. That is why the card for any meat or fish dish needs checking every week, invoice in hand. Small items like the bun and cheese matter too, because they are on every single burger.
Keep the card alive
A card that is never updated lies. Three habits are enough:
- When the meat invoice arrives, compare the price with the card. If it changed, update it.
- When you change the recipe or a side, redo the card that day.
- Once a month, weigh three plates of every main again.
With cards for the whole menu, you can see which dishes leave the most money and which sell the most, the starting point of menu engineering. To see how plate cost fits with the rest of a restaurant's numbers, read how to make a restaurant profitable.
Do it with the calculator
Put each ingredient into the food cost calculator with the price you paid and the grams on the plate, and it gives you the cost per portion. Add the fryer oil, the table extras and your waste percentage as extra lines, and you have the full card.
Frequently asked questions
Should fryer oil be part of the plate cost?
Yes. Divide what each oil change costs by the number of portions you fry in that oil. If you change 15 litres after about 200 portions of fries, each portion carries its share.
Do I use the price of whole meat or trimmed meat?
Trimmed, worked out by you. Divide the price per kilo by what you keep from each kilo after trimming. If you pay $12 a kilo and keep 850 g, your usable kilo costs $14.12.
How often should I update a plate cost card?
Whenever a main ingredient changes price noticeably, or you change the recipe or portion. For the protein, check it every week against your latest invoice.
What if the plate cost is too high for the price I charge?
You have three routes: raise the price, adjust the portion or the sides, or change an ingredient. Decide with the card in front of you, knowing how much each change moves the cost.