Prime cost is your food cost plus your labor cost, expressed as a percentage of total revenue. It’s the single most important number for understanding whether your restaurant is actually making money.

Food cost includes everything you spend on ingredients, beverages, and any items that go directly into what you sell. Labor cost includes wages, salaries, payroll taxes, and benefits for everyone from line cooks to servers to management.

These two categories typically account for 55% to 65% of revenue in a healthy restaurant. When prime cost creeps above 65%, profit margins get squeezed fast. Go above 70% and most restaurants struggle to cover rent, utilities, and other fixed costs.

The formula is straightforward: (Food Cost + Labor Cost) ÷ Total Revenue = Prime Cost Percentage

If your restaurant does $80,000 in monthly revenue with $28,000 in food costs and $24,000 in labor costs, your prime cost is 65%. That’s at the upper edge of where you want to be.

Why does this matter more than other metrics? Because food and labor are controllable. Rent is locked in. Insurance premiums don’t change month to month. But portion sizes, menu pricing, scheduling, and overtime are all things you can adjust. Restaurant accounting should give you visibility into both components so you can make informed decisions.

When prime cost runs high, the fix usually involves one of four adjustments: raise menu prices, reduce portion sizes, renegotiate with suppliers, or cut labor hours. Sometimes it’s a combination of all four.

The breakdown between food and labor matters too. Fast casual restaurants typically run higher food costs and lower labor. Full-service restaurants flip that ratio. Knowing your target for each component helps you diagnose problems faster than looking at the combined number alone.

Most restaurant owners check prime cost monthly, but weekly is better when you’re trying to bring it under control. A bad week of overstaffing or a spike in food waste shows up immediately instead of getting buried in a monthly average.

If your prime cost looks good but you’re still not profitable, the issue is somewhere else. Rent that’s too high, equipment loans, or marketing spend eating into margins. But getting prime cost right is the foundation. Everything else is harder to fix if your food and labor costs are out of line.

Tracking this consistently requires accurate books and timely financial reports. Scottsdale bookkeeping services that understand restaurant operations can help you monitor prime cost weekly or monthly so you catch problems before they become serious.