The formula
Ingredient line cost = (Quantity used / (Purchase quantity x Yield %)) x Purchase price
Total batch cost = Sum of all ingredient line costs
Cost per serving = Total batch cost / Servings produced
Why the yield step is in the formula, and why skipping it is so expensive: you do not plate what you buy. Chicken is trimmed, onions are peeled, fish is filleted. If you buy 10 pounds of chicken at 85% yield, only 8.5 pounds can ever reach a plate, so every pound you use costs the purchase price divided by 8.5, not by 10. Costing on purchase weight understates your most expensive ingredients by 15 to 40%, which is exactly where margin quietly disappears.
How to use it, with an example
- Write the recipe as the kitchen actually makes it, in one unit system. Pounds with pounds, grams with grams.
- For each ingredient, enter the quantity the batch uses, the quantity you buy at a time, the price you pay for it, and the yield after trim and peel. Use 100% for dry goods, oils and anything used whole.
- Add more ingredients with the button until the batch is complete, including the small lines: oil, seasoning, garnish.
- Enter the servings the batch really produces and the menu price, and read the cost per serving and the food cost percentage it creates.
Worked example: A chicken and rice batch uses 8 lb of chicken breast. You buy it in 10 lb packs at $38, and trimming leaves an 85% yield, so the edible pack is 8.5 lb and the chicken line costs (8 / 8.5) x $38 = $35.76. Rice: 4 lb used from a 20 lb bag at $18, a $3.60 line. Butter: 1 lb from a 5 lb block at $22.50, a $4.50 line. The batch costs $43.86 and produces 10 servings, so one serving costs $4.39. At a menu price of $15.95, the dish runs at 27.5% food cost and leaves $11.56 of gross profit a plate. The calculator above is prefilled with this recipe.
Recipe costs stay true when the recipe, the stock and the supplier prices live together. In Odoo for Restaurants, a dish is a bill of materials: the same recipe that costs the plate also draws down inventory when the Odoo POS module sells it, so theoretical usage and plate cost update with every service instead of waiting for someone to rebuild a spreadsheet.
Common mistakes
- Costing on purchase weight instead of edible weight. The classic recipe costing error, and the reason so many dishes that “cost 25%” run at 33% in the weekly numbers. Measure your own yields: whole fish fillets at 40 to 50%, whole chicken portions at 65 to 75%, peeled onions and carrots at 80 to 90%.
- Leaving the recipe card frozen while prices move. A costing is a snapshot. When chicken rises 15%, every dish containing chicken is mispriced until someone re-costs it. The full method is laid out in how to create restaurant recipes and calculate ingredient cost.
- Forgetting the invisible lines. Cooking oil, butter for the pan, seasoning, the sauce base, the garnish. On their own they look trivial; across a batch they are routinely worth two to four points of food cost.
- Costing the recipe as written, not as cooked. If the line adds a handful that the card calls 20 grams, the card is wrong. Cost the dish the kitchen produces, then fix the card, in that order. The stock habits that make usage match the card are covered in restaurant inventory management tips.
- Dividing by the servings the recipe promises. If the batch plates nine servings on a normal day, the divisor is nine, not ten. Every phantom serving understates the cost of the real ones, and how to manage food waste in restaurants shows where those missing servings usually went.
FAQs
How do I work out the yield percentage of an ingredient?
Weigh it as purchased, prepare it the way the kitchen does, and weigh what is left. Yield is usable weight divided by purchased weight, times 100. Run the test two or three times and average it.
What is the difference between recipe cost and plate cost?
Recipe cost is the whole batch: everything one full preparation costs. Plate cost, or cost per serving, is that batch cost divided by the servings it produces. Menu pricing works from the plate cost; purchasing and prep planning work from the recipe cost.
Should I add a waste or Q-factor allowance on top?
Many kitchens add 3 to 10% to the ingredient subtotal to cover the things that are impractical to weigh per dish: tasting, spills, drops and small over-portions. It is honest if your actual food cost consistently runs a little above theoretical.
How often should recipes be re-costed?
Quarterly for the full menu, and immediately when a key ingredient moves more than about 10%. Proteins move fastest and sit in the most dishes, so a protein price change is a menu-wide event, not a single-dish one.
My costed recipe says 27% but my weekly food cost is 34%. Why?
That gap is the difference between theoretical and actual food cost, and it is normal to have some. Portion drift, waste, spoilage, staff meals, comps and theft live in it.
Does recipe cost include packaging for takeout?
Not in the ingredient cost itself, but delivery and takeout packaging is a real per-plate cost, often 50 cents to over a dollar.
