Restaurant Financials: Food Cost, Labor Cost, and Prime Cost

Most businesses can absorb a bad month. A software company running an 80% gross margin can eat a rough quarter and still be fine. A restaurant usually cannot, because the gap between revenue and the cost of the food and labor it takes to produce that revenue is often only 3 to 6 percent of sales once everything else is paid. A few percentage points of drift in the wrong direction does not just dent the number, it can flip a profitable month into a losing one.

Take a single location restaurant doing $50,000 in monthly sales. If food cost runs 30% ($15,000), labor runs 32% ($16,000), and rent, utilities, insurance, and everything else runs another 24% ($12,000), the restaurant clears $7,000 in profit that month. Let food cost drift up two points, to 32%, without anyone noticing, and that is $1,000 gone, more than a seventh of the month's entire profit, from a change nobody actually decided to make.

That is not a reason to avoid the business. It is why restaurant operators who last track cost percentages weekly, not just revenue at the end of the month.

Three numbers matter more than any others: food cost percentage, labor cost percentage, and the combination of the two, prime cost. If you only ever calculate one thing in this business, calculate prime cost.

Food cost percentage is what it costs in ingredients to make a dish, divided by what it sells for. Dana runs a 60 seat Italian bistro, and her chicken parmesan uses $5.20 of ingredients per plate (chicken, breading, cheese, sauce, a side of pasta) and sells for $19. That is a food cost of about 27% ($5.20 divided by $19), which sits comfortably in the healthy range for a full service restaurant.

Most restaurants target 28 to 35% food cost overall, calculated across the whole menu rather than any single dish. A dish can run higher than that and still be perfectly fine. Dana also sells a ribeye at 38% food cost and keeps it on the menu on purpose, because guests who order it also tend to order a $14 bottle of wine and a $9 dessert, both of which run food costs under 20%. What matters is the blended number across everything sold in a shift, not any one dish judged in isolation.

Labor cost percentage is total payroll, including wages, payroll taxes, and any benefits, divided by total sales for the same period. In a slow week where Dana's bistro rings up $22,000 in sales and payroll runs $7,040, labor cost is 32%. The following week, sales jump to $31,000 for a wine dinner and a private party, and if she does not add extra kitchen and floor staff, that same $7,040 in payroll now sits at 23% of sales, not because anything got more efficient, but because the denominator grew. Labor cost percentage moves with sales volume as much as with staffing decisions, which is why it needs to be checked against the schedule, not just against last month's average.

There is no universal right number. A fine dining restaurant running a 38% labor cost is not mismanaged, that ratio is what the format requires to deliver what customers are paying for. The number only means something in the context of service style and price point, and it also starts from a different baseline depending on where the restaurant operates, since minimum wage rules for tipped staff vary by state.

Prime cost is food cost percentage plus labor cost percentage, combined into one number. In a normal week, Dana's bistro runs 27% food cost and 32% labor cost, for a prime cost of 59%, just under her target range. It is the single best early warning number in the business, because food and labor typically move against each other when someone tries to fix one in isolation. Cut a line cook's hours too aggressively during a Friday rush and the kitchen falls behind, portions get inconsistent under pressure, and food cost creeps up from waste and over-portioning by a stretched, undertrained staff working faster than they should. The labor line looks better that week. The prime cost does not.

A prime cost outside the healthy range is a starting point for a question, not an answer on its own. Food cost and labor cost drift for different reasons and get fixed in different ways, so the first step is figuring out which one is actually driving the number before changing anything.