Theoretical versus actual food cost: where the gap comes from
How to calculate both numbers, what a normal gap looks like, and the seven usual causes when it grows.
Every kitchen has two food costs. Theoretical food cost is what you should have spent if every dish were made exactly to the recipe. Actual food cost is what you really spent. The gap between them is money that left the kitchen without being sold.
How to calculate each
Theoretical food cost comes from your recipes and your sales:
Theoretical % = Σ (portions sold × recipe cost) ÷ Food sales × 100Actual food cost comes from your inventory and invoices:
Actual % = (Opening inventory + Purchases − Closing inventory) ÷ Food sales × 100Both use the same food sales figure for the same period, so the two percentages can be compared directly.
An example
| Food cost | On $142,000 in sales | |
|---|---|---|
| Theoretical | 28.4% | $40,328 |
| Actual | 31.2% | $44,304 |
| Gap | 2.8 pts | $3,976 |
That restaurant lost almost four thousand dollars in one month to things that did not appear on any guest check.
What a normal gap looks like
No kitchen hits zero. Trim varies, a sauce reduces more on a busy night, a case of herbs turns. A gap of 1 to 2 points is typical for a well-run kitchen. Above 3 points, something specific is usually going on.
The seven usual causes
- Over-portioning. A few extra grams of protein on every plate is the most common cause and the hardest to see.
- Waste that is not recorded. Spoilage, burnt batches and returned dishes all count against actual but never against theoretical.
- Recipes that do not match the line. If the recipe says 60 g of guanciale and the line uses 80 g, the theoretical number is wrong, not the kitchen.
- Outdated prices. Recipe costs calculated with last quarter’s prices make theoretical look better than it is.
- Unrecorded staff meals and comps. Food that leaves without a sale.
- Receiving errors. Short deliveries signed as complete, or invoices with prices that differ from the agreed list.
- Theft. Less common than people fear, but real, and usually concentrated in a few high-value items.
How to close it
- Keep recipes current. Update costs with every invoice, not once a quarter.
- Log waste with a reason. Spoilage, preparation error and staff meal tell you different things.
- Check the gap weekly, by category. A 2.8-point gap that is all in proteins points somewhere very different from one spread evenly.
- Investigate the top items. Look at the five items with the largest gap in money, not in percentage.
Alacena calculates theoretical and actual food cost every day, by location and category, and lists the items behind the gap so the conversation with the kitchen starts from facts.