Food cost is not a monthly number
By the time a monthly food cost percentage tells you something went wrong, the month it went wrong in is over. What to measure instead, and why the figure most kitchens use is the least useful one.
Most kitchens work out food cost once a month: everything bought, divided by everything sold, expressed as a percentage. It is the number the industry talks in, and as a management tool it is close to useless.
Not because it is wrong. Because of when it arrives.
The problem with a number that arrives in arrears
A monthly percentage is calculated after the month has closed, which in practice means somewhere between the fifth and the twentieth of the following month. So the earliest you can know that March was bad is mid-April — by which point April is half over and, if the cause is still there, April is going the same way.
Then there is the second problem: a percentage is an average, and an average hides the thing you need to see. Food cost at 34% instead of 30% on €40,000 of revenue is €1,600. That €1,600 is not spread evenly across everything you sell. It is almost always three or four specific things — one supplier price that moved, one dish that is under-priced, one item going in the bin — and the percentage tells you none of them.
The three questions worth asking instead
1. Did a price move?
This is the most common cause and the easiest to catch, because the evidence arrives in the post. A supplier bills you at a higher unit price than last time. That is a fact, visible the day the bill lands, and it does not require a month of data to notice.
The useful version of this is not "mozzarella is up 18%". It is "mozzarella is up 18%, you buy about 12 kilos a week, that is €340 a month". Now it is a decision — absorb it, change the price, or ring somebody else — rather than a complaint.
2. Is this dish actually profitable?
If a dish has a recipe attached and the ingredients have current costs, the dish has a current cost. Compare it with the menu price and you get a margin per dish, today, which moves on its own as your buying prices move.
Kitchens are regularly surprised here. The dish everybody orders is often the one with the worst margin, precisely because it was priced when the ingredients were cheaper and nobody revisited it.
3. Where is the gap between what should have gone and what did?
Recipes tell you what should have left the store room for the dishes you sold. A stock count tells you what actually left. The difference is waste, breakage, staff food, over-portioning, or a recipe that is not what the kitchen really does.
All five of those are fixable. None of them appear in a monthly percentage, which shows you a number without a cause.
What a good weekly rhythm looks like
- Price movements as they arrive, priced at your real volume.
- Dish margins recalculated whenever a cost changes, not quarterly.
- A count on the expensive things weekly — proteins, alcohol, cheese. Not
everything: the long tail is not where the money is.
- The monthly percentage kept, because you do want the trend line and your
accountant wants the figure. Just stop treating it as the thing that tells you what to do.
The point is not that monthly food cost is a bad number. It is a fine score. It is just not a coaching tool, and most kitchens are trying to use it as one.
BizBoard costs dishes from your real purchase prices, flags a supplier price rise on the bill that raised it, and puts food and labour cost next to the target you set. See how stock and recipes work.