Quick answer
Prime cost is the sum of food cost (ingredients and beverages) and total labor cost, expressed as a percentage of net sales. It's the single most important KPI because it captures a restaurant's two largest and most controllable expenses. A healthy prime cost sits between 55% and 65%: above 70% the business is in trouble.
What prime cost is and why it beats food cost
Most operators obsess over food cost and ignore prime cost. That's a mistake. Food cost tells you what you spend on ingredients, but on its own it doesn't tell the whole story. A dish with a perfect 28% food cost can still lose money if it takes three cooks and two servers to plate and deliver it.
Prime cost combines the two lines that actually weigh on the P&L: food (plus beverages) and labor. In a typical restaurant these two lines account for 55-65% of sales. Everything else — rent, utilities, depreciation, marketing — matters, but it's more fixed and harder to attack in the short term. Prime cost, by contrast, you control every single day through purchasing and scheduling.
That's why disciplined operators look at prime cost before anything else: it's the thermometer of operational profitability.
The prime cost formula
The formula is simple:
Prime cost % = (Food cost + Labor cost) / Net sales × 100
Where:
- Food cost = the cost of all ingredients consumed in the period (food and beverage), based on actual usage: opening inventory + purchases − closing inventory.
- Labor cost = the fully loaded cost of employment, not take-home pay. It includes gross wages, payroll taxes, benefits and any mandatory provisions.
- Net sales = revenue net of VAT or sales tax.
The denominator must always be net sales. Using gross is the most common error and it makes everything look rosier than it is.
A complete worked example
Take a bistro with these monthly figures:
| Line item | Amount | |---|---| | Net sales | €60,000 | | Food + beverage cost | €18,600 | | Labor cost (fully loaded) | €19,800 | | Prime cost | €38,400 |
Let's run the numbers:
- Food cost % = 18,600 / 60,000 = 31%
- Labor cost % = 19,800 / 60,000 = 33%
- Prime cost % = 38,400 / 60,000 = 64%
A 64% prime cost is at the high end of acceptable. The restaurant is profitable, but with thin safety margin: one slow month or an ingredient price spike pushes it underwater. To check your own numbers, start with the food cost calculator and the labor cost calculator, then add them up.
Targets by format
The ideal prime cost shifts with the type of operation. There's no single number that works for everyone.
| Format | Food cost | Labor | Prime cost target | |---|---|---|---| | Fine dining | 30-35% | 30-35% | 60-68% | | Full-service restaurant | 28-33% | 28-33% | 55-65% | | Casual / bistro | 30-35% | 25-30% | 55-63% | | Pizzeria | 22-28% | 22-28% | 48-55% | | Bar / café | 18-25% | 25-32% | 45-55% | | Fast casual / takeaway | 28-33% | 18-25% | 48-58% |
The underlying logic is the trade-off between food and labor. Fine dining carries high food cost because it uses premium ingredients, but also expensive, numerous staff: prime cost stays high and must be offset with higher prices and average checks. A takeaway has little front-of-house labor, so it can afford a slightly more generous food cost.
How to lower prime cost (without cutting quality)
There are two levers. Most operators only pull one.
On food cost:
- Standardize recipes with spec sheets and portion control, eliminating the "by eye" plating that erodes margins.
- Negotiate with suppliers and consolidate orders for better pricing.
- Attack waste: trim loss, spoilage, kitchen errors. A waste audit often recovers 2-3 points of food cost.
- Run menu engineering: push high-margin dishes and cut or re-price the losers.
On labor cost:
- Build schedules on actual traffic data, not habit. Overstaffing during slow periods is the number one killer.
- Measure productivity with sales per labor hour.
- Cross-train staff so fewer people cover more roles at peak.
- Watch overtime, which usually weighs more than it appears.
The golden rule: never cut quality to chase prime cost. A worse dish lowers the check and the reviews, and the cure becomes worse than the disease.
Prime cost and menu pricing
Prime cost also tells you whether your prices hold up. If you know your format's target, you can work backwards. Example: if you want a 60% prime cost and a dish has a combined cost (ingredients + estimated labor share) of €6, the minimum net selling price is:
Net price = combined cost / prime cost target = 6 / 0.60 = €10
Add VAT to reach the menu price. This method beats pricing dishes "by feel" or copying competitors, which is the fastest way to end up with broken margins.
Common mistakes
- Watching food cost only. It's half the story. Textbook food cost with runaway labor still produces losses.
- Calculating on gross sales. It inflates the denominator and hides problems. Always net of tax.
- Using take-home pay for labor. The real cost of employment includes taxes, benefits and provisions: often 35-45% above net pay.
- Only reviewing at year-end. By then the damage is done. Read prime cost weekly, or monthly at the very least.
- Benchmarking against the wrong format. A bar isn't a fine-dining room. Use your segment's targets.
- Cutting quality to balance the books. It's a boomerang: the check drops, reviews drop, sales drop.
Related resources
To calculate your numbers and build your restaurant's prime cost:
- Food cost calculator — work out ingredient cost and its percentage of sales.
- Labor cost calculator — estimate the fully loaded cost of staff, taxes and provisions included.
Add the two results, divide by net sales, and you have your prime cost. Track it every month: it's the number that tells you, before any other, whether your restaurant is truly making money.