How to Calculate Food Cost Per Dish (Step-by-Step)

Why Dish-Level Costing Is the Foundation of Profitability

Restaurant-level food cost percentage tells you how you did. Dish-level food cost tells you why — and where to act. A restaurant running 34% food cost can identify which specific dishes are driving that number only if every dish has been costed individually.

Plate costing (also called recipe costing or dish costing) is the process of calculating exactly how much it costs to produce one serving of a menu item. This number, combined with your selling price, gives you the food cost percentage and contribution margin for every dish on your menu.

Step 1: List Every Ingredient

Start with your standardized recipe. List every ingredient that goes into one portion of the dish — not just the proteins and starches, but the finishing oil, the garnish, the sauce, the bread accompaniment. Small items add up.

Example: Grilled Salmon with Lemon Butter Sauce

• Atlantic salmon fillet — 180g (as-purchased weight: 220g for 82% yield)
• Butter — 25g
• Lemon — 0.25 lemon
• Garlic — 5g
• White wine — 30ml
• Parsley — 3g
• Salt and pepper — 2g
• Olive oil — 5ml

Step 2: Account for Yield and Waste

This is where most manual costing goes wrong. If your salmon fillet yields 82% usable fish from the as-purchased weight, you need to cost the as-purchased quantity, not the as-served quantity.

As-Purchased Cost = (As-Served Weight / Yield %) × Price Per Unit

If salmon costs $22/kg and you need 180g as-served with an 82% yield:

As-Purchased Weight = 180g / 0.82 = 220g. Cost = 220g × $0.022/g = $4.84

Step 3: Calculate Cost Per Ingredient

For each ingredient, calculate the cost at the recipe quantity:

• Salmon (220g at $22/kg): $4.84
• Butter (25g at $12/kg): $0.30
• Lemon (0.25 lemon at $0.80 each): $0.20
• Garlic (5g at $8/kg): $0.04
• White wine (30ml at $8/750ml bottle): $0.32
• Parsley (3g at $15/kg): $0.05
• Salt/pepper (2g at $3/kg): $0.01
• Olive oil (5ml at $10/L): $0.05

Total plate cost: $5.81

Step 4: Add Sub-Recipe Costs

Many dishes use prepared components — stocks, compound butters, house-made sauces — that have their own recipe costs. If your lemon butter sauce is made in batches, calculate the batch cost and divide by the number of portions it yields to get the cost per portion.

Example: Your lemon butter sauce recipe makes 20 portions at a total ingredient cost of $8.00. Cost per portion = $0.40. Add this to your dish cost instead of costing the individual sauce ingredients each time.

Step 5: Calculate Food Cost Percentage

Food Cost % = Plate Cost / Selling Price × 100

If your salmon dish sells for $24 and costs $5.81 to produce (plus $0.40 sauce sub-recipe = $6.21 total):

Food Cost % = $6.21 / $24.00 × 100 = 25.9%

At 25.9%, this dish is performing well — below the 30% target. The contribution margin is $24.00 − $6.21 = $17.79 per portion.

Step 6: Set or Validate Your Menu Price

Working backwards: if you want to hit a 30% food cost target and your plate cost is $6.21:

Target Menu Price = $6.21 / 0.30 = $20.70

At $24, you are beating the target. At $18, you would be at 34.5% — above target. This calculation tells you whether your current price is appropriate or needs adjustment.

Why to Use Software Instead of Spreadsheets

Manual plate costing in spreadsheets works for a 10-dish menu reviewed quarterly. It breaks down for a 60-dish menu with daily ingredient price fluctuations.

Karu automates every step: enter your recipes once, link ingredients to current supplier pricing, and the system calculates plate cost and food cost percentage automatically. When your salmon supplier increases their price, every salmon dish recalculates in seconds. You see which dishes are now above target and can adjust prices or substitute ingredients proactively.