The restaurant food cost formula (with calculator)

The food cost formula is straightforward and still gets used wrongly more often than not. Cost of goods sold equals opening inventory plus purchases minus closing inventory. Food cost percentage equals cost of goods sold divided by net food sales for the same period, multiplied by one hundred.

The common error is skipping inventory and dividing purchases by sales. That tells you what you bought, not what you used. A heavy delivery on the last day of the month can add three points to a number that never left the walk-in, and a light buying week can hide a real problem for another thirty days.

Targets depend on format and on what the check average supports. Full-service independents generally aim for 28 to 32 percent. Fast-casual runs 25 to 30. Coffee shops sit around 22 to 28 on food and lower on beverage. Bars should keep liquor between 18 and 24, bottled beer around 24 to 28, and wine anywhere from 28 to 35 depending on list strategy. Steakhouses and seafood-led establishments routinely run 34 to 40 and make it work through ticket size, not through discipline alone.

Two other numbers belong beside the percentage. Theoretical food cost is what your recipes say you should have spent given what you sold; the gap between theoretical and actual is your waste, over-portioning, comps and theft, and it is where most recoverable money lives. Contribution margin — menu price minus plate cost, in dollars — is what actually pays the rent, and it is why a 38 percent item at a $19 margin can beat a 24 percent item at a $6 margin.

Count inventory on the same day of the week, at the same time, with the same person leading it. Consistency matters more than precision here, because you are reading the trend. Weekly counts on the top twenty items by spend will get you eighty percent of the value of a full count at a fraction of the effort.

When the number moves, work through the causes in order of likelihood: supplier price increases that were never re-quoted, portion drift on your highest-volume items, prep waste and yield loss, unrecorded comps and staff meals, then theft. Re-costing recipes annually and re-quoting the top ten purchase lines every six months removes most of the drift before it compounds.

Use the calculator below to run your own period, then compare the result against the target for your format. If the gap is more than two points, it is worth a proper look at recipes and purchasing rather than another round of menu price increases.