How to cost a dish and keep kitchen waste under control
Standard recipe, ingredient yield, cost per portion, food cost and suggested price, with a worked example and a method to make waste visible.
You’re selling more than last month, yet the margin keeps shrinking. The chicken supplier raised prices two months ago and the menu hasn’t changed. In the kitchen, every cook serves “a portion” their own way, and at closing a pot of rice nobody logged goes in the bin. When someone asks what the best-selling dish costs, the answer is a figure worked out a year ago using the weight of the chicken breast as delivered, bone and skin included.
This guide explains, step by step, how to calculate the real cost of a dish and how to control waste. All of it can be done in a spreadsheet.
The concepts you need
- Standard recipe (recipe card): the list of ingredients in a dish with the exact quantity per portion, the preparation method and a photo of the plating. Without it, every cook makes a different dish and no cost figure can be trusted.
- Gross weight: what you buy (the whole breast, the lettuce with its outer leaves).
- Net weight: what actually reaches the plate after trimming, peeling or deboning.
- Yield: the percentage that remains usable.
Yield (%) = net weight ÷ gross weight × 100
The key point: a usable kilo always costs more than a purchased kilo.
Cost per net kg = price per gross kg ÷ yield
If you buy chicken breast at Bs 36 per kilo and, after trimming, 10 kg leaves you with 7.5 kg, the yield is 75% and each usable kilo costs you 36 ÷ 0.75 = Bs 48, not Bs 36.
Step-by-step method
- Write the standard recipe for each dish: ingredient, net quantity per portion and unit.
- Measure the yield of your main ingredients. Weigh a real purchase before and after trimming, repeat three or four times and use the average. Don’t copy yields from the internet: they depend on your supplier and your kitchen.
- Calculate the cost per net kg of each ingredient with the formula above and the price of your latest purchase.
- Add up the cost per portion: net quantity × cost per net kg, ingredient by ingredient. Include oil, seasoning, sauces and, if you sell takeaway, the packaging.
- Set your target food cost and calculate the suggested price.
- Log waste every day.
- Compare theoretical and actual usage every week.
Worked example: grilled chicken with rice and salad
Assume the following prices and yields (hypothetical figures):
| Ingredient | Price per gross kg | Yield | Cost per net kg | Net quantity per portion | Cost per portion |
|---|---|---|---|---|---|
| Chicken breast | Bs 36.00 | 75% | Bs 48.00 | 180 g | Bs 8.64 |
| Rice | Bs 10.00 | 100% | Bs 10.00 | 80 g (raw) | Bs 0.80 |
| Tomato | Bs 8.00 | 90% | Bs 8.89 | 60 g | Bs 0.53 |
| Lettuce | Bs 12.00 | 70% | Bs 17.14 | 40 g | Bs 0.69 |
| Oil and seasoning | — | — | — | estimate | Bs 0.60 |
| Total | Bs 11.26 |
Look at the lettuce: per kilo purchased it seems cheap, but with a 70% yield each usable kilo costs more than Bs 17.
Food cost and suggested price
Food cost (%) = ingredient cost ÷ selling price × 100
Suggested price = cost per portion ÷ target food cost
If your target food cost is 30%, the suggested price is 11.26 ÷ 0.30 = Bs 37.53. You round it to Bs 38 and your food cost ends up at 11.26 ÷ 38 = 29.6%.
Two caveats. First, this price is before taxes: how VAT is reflected in the menu price depends on your situation, so confirm it with your accountant (there’s background in VAT and net pricing). Second, the target food cost is not a universal rule: it depends on your format, your rent and your staff. Also look at the margin in bolivianos (38 − 11.26 = Bs 26.74): a dish with a high food cost can leave more money per unit than one with a low food cost.
Waste: types and how to log it
Waste is any ingredient you bought that didn’t end up sold on a plate. Not all of it is the same:
| Type | Example | How to control it |
|---|---|---|
| Prep | Skin, bones, peels | Already in the yield; if it rises, check the supplier or the cutting technique |
| Cooking | Weight lost during cooking | Measure it once and adjust the recipe |
| Spoilage or expiry | Wilted vegetables, expired dairy | Rotation by date (see FEFO vs FIFO) and tighter purchasing |
| Errors | Burnt dish, wrong order, return | Log with reason and person responsible |
| Overproduction | Rice or sides prepared and not sold | Prepare in batches based on sales per hour |
| Over-portioning | Portions larger than the recipe | Scales and measuring utensils on the line; it shows up in no log |
To log it, a daily sheet is enough: date, ingredient, quantity, unit, type of waste, reason and who logged it. At the end of the week, value each line at the cost per net kg and sort from highest to lowest. Three or four ingredients almost always explain most of the loss.
Theoretical vs actual inventory
Theoretical usage is what you should have used based on what you sold; actual usage is what you did use based on your inventory.
- Theoretical usage = dishes sold × net quantity per portion ÷ yield
- Actual usage = opening inventory + purchases − closing inventory
Assume a week with 400 chicken dishes sold:
- Theoretical chicken breast usage: 400 × 0.18 kg ÷ 0.75 = 96 kg gross.
- Actual usage: 30 kg opening + 100 kg purchased − 22 kg closing = 108 kg.
- Difference: 12 kg (12.5% over theoretical), about Bs 432 at purchase price.
- Waste logged during the week: 5 kg (2 kg burnt, 3 kg expired).
- Unexplained difference: 7 kg.
Those 7 kg are the question of the week. The usual causes: portions larger than the recipe, a real yield lower than the one you used for costing, waste nobody logged, counting errors or shrinkage. If the gap repeats, weigh portions in the middle of the rush and measure the yield again.
The same logic gives you the actual food cost for the period: actual usage at cost ÷ food sales. If theoretical is 30% and actual is 34%, those four points are money lost between purchase and plate.
Common mistakes
- Costing with gross weight as if it were net: the dish looks cheaper than it is.
- Not updating costs when supplier prices change. Every time one of your biggest-cost ingredients goes up, review the recipes that use it.
- Forgetting the small stuff: oil, salt, sauces, napkins and takeaway packaging add up.
- Measuring food cost with the month’s purchases only, without a physical count at the start and end.
- Logging waste without valuing it: “3 kg of tomato” doesn’t catch anyone’s eye; “Bs 80 a week” does.
- Not keeping the recipe visible on the kitchen line: if the cook can’t see it, they won’t follow it.
Weekly checklist
- Standard recipes updated with the latest purchase price.
- Yield of the main ingredients measured within the last month.
- Waste sheet complete and valued.
- Physical count of the ten highest-cost ingredients.
- Theoretical vs actual comparison done, with the unexplained difference investigated.
- Dishes with food cost above target reviewed (price, portion or recipe).
Taking it into a system
A well-kept spreadsheet is enough to start. When you run several branches or a central kitchen, an ERP like MKA can store each recipe as a bill of materials and record waste and cost on every production order (see production orders).