A busy night with a full dining room feels like a good night, and often it is — but revenue alone doesn't confirm profitability in a restaurant the way it might seem to. Prime cost, the combined total of food cost and labor cost as a percentage of revenue, is the number that actually reflects whether a given day or shift was genuinely profitable.
What counts as a healthy prime cost
Prime cost in the 55-60% range is generally considered healthy for full-service restaurants, with some variation by concept and service style — quick-service and fast-casual formats often run lower. A prime cost consistently above roughly 65% is typically a sign that either food cost, labor cost, or both need attention, since there's less margin left to cover rent, utilities, and other fixed costs.
Why splitting it into food cost and labor cost separately matters
A high prime cost with healthy food cost but elevated labor cost points to a scheduling or staffing efficiency issue; the reverse — healthy labor cost but high food cost — points toward portioning, waste, or a pricing problem on the menu. Looking only at the combined prime cost number without breaking it into its two parts can leave the actual cause unclear.
Why Front of House vs. Back of House labor needs its own breakdown
Labor cost alone can mask which side of the operation is actually driving an overage — a kitchen running heavy on labor relative to volume is a different problem, with a different fix, than a front-of-house staffing pattern that doesn't match the shift's actual traffic.
Why daily tracking catches problems a monthly P&L can't
Prime cost is one of the fastest-moving numbers in restaurant operations — a single bad shift, a delivery price spike, or an overstaffed slow night shows up immediately in daily prime cost but gets diluted into invisibility in a monthly average. Tracking it daily is what actually shows why a bad day happened, not just that the month, in aggregate, was fine.