Per plate
food cost % = plate cost / menu price x 100 $2.90 plate at a $12.00 price -> 2.90 / 12.00 x 100 = 24.2%
This is the version everyone knows, and it is only as honest as the plate cost you feed it. A plate cost typed into a spreadsheet from memory — flour at “about 10 cents”, chicken with no trim loss — produces a percentage with one decimal place of false confidence. Plate cost is itself a computation: pack price to per-unit cost, quantity used, and yield. The food cost calculator does that chain properly, and then this formula is worth running.
Per period — the version that catches waste
cost of food sold = opening inventory + purchases - closing inventory food cost % = cost of food sold / food sales x 100 $4,200 opening + $9,100 purchases - $3,900 closing = $9,400 used $9,400 / $31,000 sales x 100 = 30.3%
The period version counts what actually left your shelves, not what recipes say should have. Run both: the per-plate number is your theoretical cost, the period number is your actual, and the gap between them is waste, over-portioning and shrinkage made visible. A theoretical 26% against an actual 31% is five points of sales walking out the back door — on $30,000 of monthly sales, about $1,500 a month, findable only because you computed the formula twice.
Rearranged for pricing
menu price = plate cost / (target % / 100) $2.90 plate at a 28% target -> 2.90 / 0.28 = $10.36
Same formula, solved for price. The menu pricing calculator runs it against a ladder of targets and shows the margin each price leaves — because a percentage target optimised without looking at dollars is how a menu ends up proud of its ratios and short on rent.
The two inputs that make it wrong
Yield. If a recipe needs 400 g of trimmed meat from a 65%-yield bird, the plate must carry the cost of 615 g. Every yield you skip understates cost — always downward, never up, which is why the error survives: it flatters.
Stale pack prices. The formula is recomputed at menu-print time; your supplier reprices quarterly. A plate cost built on last winter’s invoice is not a cost, it is a memory. This is the actual argument for keeping prices in one place — in LineCost Pro a price book does it and every dish recomputes when an invoice changes.
Common questions
- What is the basic food cost formula?
- Food cost % = (cost of food sold ÷ food sales) × 100. Per plate, that is plate cost ÷ menu price × 100. Per period, cost of food sold = opening inventory + purchases − closing inventory, which catches waste and theft that the per-plate version cannot see.
- What is the formula for pricing from a target food cost?
- Menu price = plate cost ÷ (target % ÷ 100). A $2.90 plate at a 28% target prices at $10.36. It is the same formula rearranged — which is why an honest plate cost matters more than the arithmetic.
- Why do my two food cost numbers disagree?
- The per-plate (theoretical) number assumes perfect portioning and zero waste; the period (actual) number counts everything that left the shelf. The gap between them is your waste, over-portioning and shrinkage — tracking both is precisely how you see it.