The food cost formula
Actual food cost for a period is beginning inventory plus purchases minus ending inventory. Divide that by food sales for the same period and you have your food cost percentage. If you started the month with $8,000 of food inventory, bought $22,000 and ended with $7,000, your food cost was $23,000. On $70,000 of food sales that is about 32.9%.
That single number tells you whether you have a problem, but not where it is. Is the menu priced too low? Are portions drifting? Is product spoiling or walking out the back door? Recipe costing is how you break the number apart. Many operators target a food cost somewhere in the high 20s to mid 30s as a percentage of food sales, but the right target depends on your concept, price point and labour model, so compare yourself mainly against your own trend.
Cost every recipe down to the gram
A recipe card lists every ingredient in a dish, the quantity used, and the cost of that quantity. Add them up and you have the plate cost. Divide plate cost by menu price and you have that dish’s food cost percentage. Do this for every item on the menu, including sides, sauces and garnishes, because those small items are where cost hides.
Use the edible portion cost, not the as-purchased cost. If you buy a case of whole salmon at $14 per pound but only 60% of it ends up as usable fillet after trimming, the real cost of usable salmon is about $23.33 per pound. Measure the yield of your high-cost proteins and produce by testing them yourself; supplier estimates are a starting point, not a substitute.
Build sub-recipes for anything you prep in batches, such as a house sauce or dough. Cost the batch once, divide by the yield, and use that per-unit cost in every dish that includes it.
- As-purchased price from the latest supplier invoice
- Yield percentage after trimming, cooking and portioning
- Edible portion cost = as-purchased cost ÷ yield
- Portion quantity in grams, millilitres or units
- Sub-recipe cost per portion for sauces and prep items
Compare theoretical and actual food cost
Once every item has a recipe, you can calculate theoretical food cost: what your food should have cost given exactly what you sold. Multiply each item’s plate cost by the number sold (your POS item sales report gives you this), add them up, and divide by food sales.
The gap between theoretical and actual food cost is your variance. A small gap is normal. A large one points to over-portioning, waste, spoilage, theft, unrecorded comps, or recipes that no longer match what the kitchen actually does. Track the variance every week or every month; the trend tells you whether changes are working.
A POS with ingredient-level inventory does much of this automatically. In SeroPOS, recipes link menu items to ingredients, so each sale deducts stock and the system can show expected usage against your counts. Recipe management is part of the SeroPOS Pro plan.
Find and fix the leaks
Start with a waste log. Keep a sheet or tablet by the line where staff record anything thrown out: the item, quantity and reason (overproduction, spoilage, dropped, returned by guest). Within a few weeks you will see patterns, such as a prep item made in batches too large for weeknight volume.
Then look at portioning. Scales, portion scoops and ladles, and plating photos at each station keep portions consistent between cooks. Spot-check portions during service. A burger that goes out with 10% more beef than the recipe card is a 10% higher protein cost on every one sold.
Finally, tighten receiving and storage. Check deliveries against the invoice and purchase order for weight, count and quality before signing. Rotate stock first in, first out, label and date prepped items, and lock high-value items like proteins and alcohol.
Watch supplier prices
Recipe costs are only as accurate as the prices behind them. When a supplier raises the price of a key ingredient, every dish that uses it gets more expensive. Update ingredient costs from invoices regularly, ideally every time you receive, and review the dishes most exposed to volatile ingredients like proteins, dairy, cooking oil and produce.
Get quotes from more than one supplier for your top 20 items by spend. You do not need to switch suppliers constantly, but knowing the market price gives you something to negotiate with. Purchase orders also help: if you order from a list with expected prices, any price change on the invoice stands out.
Use menu engineering to price and position dishes
Menu engineering combines each dish’s contribution margin (menu price minus plate cost) with its popularity. Dishes that are popular and profitable are your stars: keep them prominent. Popular but low-margin dishes (often called plowhorses) are candidates for a small price increase or a recipe tweak. Profitable but unpopular dishes (puzzles) may need better placement or a better description. Dishes that are neither are candidates to remove.
Look at contribution margin in dollars, not just percentages. A steak at 40% food cost may still earn more dollars per plate than a pasta at 22%. The goal is to maximize total gross profit, not to hit a percentage on every line.
Make it a routine
Food cost control works when it is routine. Count high-value items weekly and do a full inventory monthly, on the same day and at the same point in service. Update recipe costs when prices change. Review the variance and the waste log with the chef every week, and post your food cost to the books every month so your P&L reflects reality.
Connecting inventory to accounting closes the loop. When purchases and counts flow into your books, cost of goods sold on the P&L matches what the kitchen measured. SeroPOS includes built-in reporting and syncs with SeroBooks, QuickBooks Online or Xero for that purpose.
- Weekly: count proteins and alcohol, review waste log
- Weekly: compare theoretical and actual food cost
- On every delivery: check invoice prices against recipes
- Monthly: full inventory count and P&L review
- Quarterly: menu engineering review and price changes