Food Cost Percentage Formula (With a Worked Example)

Every restaurant owner has done the math at least once. Numerator over denominator, plug in beginning inventory plus purchases minus ending inventory, divide by food sales. The result is a number. The number is also, in most indie restaurants, three weeks late and silent about what's happening this Tuesday. This is a walk through the formula on a real bistro's numbers — and the three places it silently goes wrong.

The formula, written out

The standard formula is:

Food Cost % = (Beginning Inventory + Purchases − Ending Inventory) ÷ Food Sales × 100

That's it. The numerator — beginning inventory plus purchases for the period minus ending inventory — is your Cost of Goods Sold (COGS). Divide by food sales for the same period. Multiply by 100 to get a percentage instead of a decimal. The math takes thirty seconds; the accuracy lives entirely in the inputs.

A worked example: a 60-seat bistro, one week

Let's run a real-feeling example. Casual bistro, 60 seats, lunch + dinner, four nights a week of full covers. The numbers below are rounded but representative of what a $50,000-a-week operation actually looks like.

• Beginning inventory (Monday morning): $12,400
• Purchases (Tuesday-Sunday supplier invoices): $15,800
• Ending inventory (next Monday morning): $11,200
• Food sales (POS report, same period): $54,000

COGS = $12,400 + $15,800 − $11,200 = $17,000.

Food cost percentage = $17,000 ÷ $54,000 × 100 = 31.5%.

For this operator, 31.5% is inside the target band (28–32%) — they look fine. Now the part where the math quietly lies.

Where the formula silently goes wrong

Three places. Each one is small on its own and devastating in combination.

1. Inventory snapshots that aren't actually snapshots

The formula assumes beginning and ending inventory are measured at the same level of accuracy and at the same moment in the week. In practice, beginning inventory is usually a careful count and ending inventory is whatever the closing manager wrote down at 11pm on Sunday after a six-hour service. The variance between those two counts is real — even on a tightly-run kitchen, expect 1–2% noise introduced just from inconsistent count cadence. On a $54,000 weekly sales operation, 2% noise on a $11,000 ending inventory figure is $220 — which moves food cost % by 0.4 points without anything actually changing in the kitchen.

2. Purchases that haven't been entered yet

If three supplier invoices arrived Friday and haven't been entered by Monday morning's calculation, your purchases line is understated and your food cost % looks better than it is. This is the single most common error in indie restaurant food cost reporting, and it's the structural reason food cost reporting defaults to monthly cadence — by month-end, every invoice has usually caught up. The fix isn't to wait; the fix is to make invoice capture frictionless enough that it happens the same day. We walk through that loop in How to Update Your COGS in 8 Seconds.

3. The sales-side problem nobody talks about

Your sales denominator is supposed to be net food sales — POS sales minus voids, comps, discounts, and any non-food items the POS bundles in. If your POS report includes beverage sales, your food cost percentage is understated. If it doesn't strip comps, it's understated again. A 5% comp rate (normal for a hospitality-heavy operation) inflates the denominator by 5%, which deflates food cost % by roughly the same. Suddenly 31.5% is actually 33.1% — and the operator is making margin decisions on the wrong number.

What “good” food cost percentage looks like by restaurant type

The 28–32% range is the most-cited target, but it's deliberately wide because the right number depends on your concept. A useful rule of thumb, drawn from cross-segment benchmarking:

The targets are starting points. If you're 4 points outside the range for your concept, you have a margin problem; if you're 8 points outside, you have a structural problem — wrong menu pricing, wrong portion sizes, or both.

Why the formula isn't enough on its own

Even calculated perfectly, the formula tells you what happened last week. It doesn't tell you what's happening today, and it doesn't tell you where the variance lives — which dishes are carrying the worst cost, which suppliers are silently drifting prices upward, which line cook is overportioning the expensive ingredients. The formula is the headline; the variance breakdown is the story. For the deeper read on why your food cost percentage can be numerically correct and operationally useless, see Why Your Food Cost Percentage Lies.

That's the math. The 30 seconds of arithmetic isn't the work — the work is the inputs, and the inputs are where the entire 2026 indie operator playbook lives. Get the inputs right (daily invoice capture, clean inventory counts, a sales denominator that actually means food sales) and the formula tells you the truth. Get them wrong and you're making decisions on a number that lies politely.