Portion Calculator for Restaurants

① The chain of three weights: what you buy is not what you serve

Three items weighed in the kitchen, not estimated. Purchase, trimmed, servable — and the portions left at the end of that chain.

The naive arithmetic is off by a third. Dividing 6,000 g by 120 g gives 50 portions of round, and the scale says 36. Fourteen portions of difference on a single case: that is what gets under-ordered when the order is built on invoice weight instead of servable weight. On trout the gap is worse —25 against 14— which is why it is the expensive dish that runs out on Sunday, not the cheap one.

SUPUESTO: the three factors come from a weighing done in Sazón de Origen's own kitchen, not from an industry yield table, which shifts by cut, by supplier and by country. If the round supplier starts sending a fattier cut and the factor drops from 0.74 to 0.68, each case goes from 36 to 33 portions and Sunday's order rises by a full case. That is why the factor is re-weighed every month and every time the supplier changes: it is not a filing-cabinet number, it is a number that expires.

② Sunday, dish by dish and channel by channel

214 covers forecast across both locations for Sunday lunch, split with the sales mix of the last 8 weeks.

The cushion is not spread evenly, and that is this block's decision. The sancocho carries 6 because it is the one that ran out, and being without it on a Sunday costs the contribution margin of 6 plates plus the face of the guest who came for it. The trout carries 2: every spare portion is $12,179 heading for the walk-in and from there to the bin, because portioned fillet does not survive to Tuesday. And the platform carries no cushion on any dish — if it sells out, the item is switched off in the app and nothing happens; in the dining room, switching an item off means saying no to somebody already seated.

③ The purchase list, already rounded to the case they sell you

The arithmetic reversed: portions × gram weight ÷ factor, then rounded to the unit the supplier invoices. The rounding is the part that eats the saving.

On the bandeja the rounding forces a choice, and the choice gets written down. 12.49 kg are needed and the case is 6 kg: two cases leave you 3 portions short, three cases leave 5.51 kg standing, which at $38,000 a kilo is $209,000 waiting for the week to use it. Two cases are ordered and the 3 portions come out of the dining room cushion, which was set at 3 for exactly this. The other way out is negotiating half a case with the supplier, and that is a purchasing conversation, not a kitchen one.

All three stay under the 32% set by the house costing rule, and that is the uncomfortable finding: weighing the yield barely moved the food cost — it moved the order. The error was never in the cost of the dish, it was in the quantity coming through the back door.