Restaurant Food Cost Formula — The Complete Guide

1. Per-Item Food Cost Percentage

This tells you what percentage of a single dish’s revenue goes to ingredients. Use it when pricing new items or evaluating existing ones.

A $28 salmon with $8.50 in ingredients: $8.50 ÷ $28.00 × 100 = 30.4%. That means 30 cents of every dollar from that dish covers the raw fish, sauce, and sides. The remaining 70 cents covers labor, rent, and — hopefully — profit.

2. Overall Food Cost Percentage

This measures your entire restaurant’s food cost for a given period (usually a week or month). It accounts for waste, theft, over-portioning, and everything else that per-item calculations miss.

Start of week inventory: $12,000. Purchases during the week: $6,500. End of week inventory: $10,200. COGS = $8,300. If food sales were $27,000, your overall food cost was 30.7%. If this number is higher than your per-item average, the gap represents waste, theft, or portioning errors. Track it weekly without exception.

3. Ideal (Theoretical) Food Cost

This is what your food cost should be if there were zero waste, zero theft, and perfect portioning. Calculate it by multiplying each item’s per-unit ingredient cost by the number sold, then dividing by total food revenue.

If your ideal food cost is 27% but your actual is 32%, you have a 5-point gap. That gap is pure operational loss — waste, spoilage, over-portioning, or unrecorded comps and employee meals. On a restaurant doing $20,000/week in food sales, a 5-point gap costs you $1,000 per week, or $52,000 per year. Read our guide to reducing food cost to close that gap.

4. Contribution Margin

This tells you how many dollars each item contributes toward covering overhead and generating profit. It is the number used in menu engineering to classify Stars, Plowhorses, Puzzles, and Dogs.

A $22 chicken parmesan with $6.50 in ingredients has a $15.50 contribution margin. A $16 burger with $6.40 in ingredients has a $9.60 contribution margin. Even though the burger has a similar food cost percentage (40% vs. 29.5%), the chicken contributes $5.90 more per plate. When you sell 100 of each per week, that is $590 more weekly profit from the chicken.

5. Menu Price from Target Food Cost

When pricing a new menu item, use this formula to calculate the minimum price needed to hit your target food cost percentage.

If ingredients cost $7.20 and you target 28% food cost: $7.20 ÷ 0.28 = $25.71. Round to $26. If you target 32%: $7.20 ÷ 0.32 = $22.50. That $3.50 difference in price per plate, across 80 weekly sales, is $14,560 per year. Choosing the right target — informed by your restaurant type benchmarks — is essential.

6. Plate Cost (Cost Per Serving)

The total cost of every ingredient on the plate, accounting for trim, waste, and cooking yield. This is the most accurate input for all the formulas above.

A 5 lb bag of flour costs $4.50. Your recipe uses 0.3 lb. Flour cost per plate: $4.50 × (0.3 ÷ 5) = $0.27. Do this for every ingredient and sum them up. For proteins, account for trim and cooking loss — a 10 oz raw chicken breast yields roughly 7.5 oz cooked. If you need 6 oz on the plate, you need to start with 8 oz raw. Price accordingly. Learn more in our plate cost calculator guide.

Putting the Formulas Together

Each formula is a lens on the same underlying question: is this restaurant making money on food? Use plate cost to calculate accurate per-item food cost percentage. Use per-item food cost percentage to set menu prices. Use ideal food cost to benchmark against actual food cost. Use the gap between ideal and actual to find operational problems. Use contribution margin for menu engineering. And track overall food cost weekly to confirm the whole system is working. Miss any one of these and you have a blind spot. For the complete picture, read our food cost guide.