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 good 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. 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. The error survives review because the flattering direction never looks wrong.
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 A plate cost built on last winter’s invoice is out of date, not merely imprecise. 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.