Cost of goods sold (COGS) is the dollar value of food and beverage used during a period — not the dollar value purchased.
Formula: COGS = Beginning Inventory + Purchases − Ending Inventory
Why COGS is not the same as purchases
Operators who use weekly invoice totals as a proxy for COGS systematically misstate their food cost percentage. Real audits show 1–5 point swings in either direction depending on inventory cycle and seasonality. A week with heavy stocking before a holiday inflates purchases without inflating actual cost. A week immediately after a big inventory drawdown understates purchases relative to actual usage.
The reconciliation: what you used (COGS) ≠ what you bought (purchases). The difference is the inventory swing.
How to calculate COGS
- Beginning inventory: dollar value of food, non-alcohol beverage, and alcohol on hand at the start of the period — counted, not estimated.
- Purchases: total invoices received during the period (food, beverage, and alcohol broken out separately if you track each cost band).
- Ending inventory: dollar value on hand at the end of the period — counted again.
- COGS = Beginning + Purchases − Ending.
Example: $5,000 beginning inventory, $14,000 purchases, $5,500 ending inventory. COGS = $5,000 + $14,000 − $5,500 = $13,500. The $14,000 in purchases is not your cost; the $13,500 used is.
COGS calculator
Plug in your weekly numbers. The calculator returns COGS dollars and cost percentage, then flags the result against industry-standard ranges for the category.
Inside the operational target band (28–32% food cost).
Industry ranges are operational targets for full-service independents, drawn from NRA Restaurant Operations Data Abstract benchmarks.
Why weekly inventory cycles matter
The longer the gap between counts, the larger the variance window. Operators on a monthly cycle can't tell whether a 4-point swing in food cost percentage came from a real cost issue or just from the timing of a Thursday delivery vs. a Tuesday delivery on either side of the period boundary. Weekly counts close that window. Operators who count only quarterly are essentially flying blind on COGS.
Common operator mistakes
- Treating purchases as cost. Purchases are an input; cost is what was used. Misstating this propagates into food cost %, prime cost, and every downstream metric.
- Skipping the count. An "estimated" inventory number defeats the purpose. Either count, or accept that food cost % is an approximation.
- Counting at inconsistent times. Counting Sunday night one week and Monday morning the next adds noise. Same time, same day, every week.
Related concepts
- Food cost percentage — COGS divided by food sales
- Prime cost — COGS plus labor
- Weekly inventory audit — the count discipline that makes COGS reliable
- How do I automate food cost management? — the operational loop around COGS