Record purchase units before converting
Start with the supplier invoice: pack price, net quantity, unit, currency, and date. A 2 kg pack costing $18 has an as-purchased cost of $9/kg. Convert recipe grams to kilograms before multiplying; 250 g is 0.25 kg. A pack count is not a weight, so weigh a representative item if the recipe uses grams but the supplier sells pieces.
Measure usable yield, then cost the amount used
Suppose the 2 kg pack leaves 1.8 kg after preparation. Yield is 1.8 ÷ 2 = 90%, and usable cost is $18 ÷ 1.8 = $10/kg. A recipe using 250 g of that prepared ingredient costs $2.50, not $2.25. Record the raw and prepared weights from the same batch. Do not apply the same trim loss again if the recipe quantity already includes it.
Complete a batch and divide by saleable output
In a fictional soup batch, prepared vegetables cost $2.50, stock $4.80, seasoning $0.70, and other ingredients $4.00: total $12.00. Ten saleable servings cost $1.20 each. If the actual saleable yield is nine, the cost is $1.33 each. Keep production losses in the batch total and use the measured finished output.
Turn the record into a repeatable check
Keep the invoice date, preparation yield, batch size, and portion weight together. Weigh portions during a normal service, not only a careful test batch. Recalculate after a pack-size, supplier, recipe, or portion change. Add labor and packaging separately before pricing; the $1.20 figure describes ingredients only, not the full cost of a sale.
Use your own operating data
Supplier prices, yields, labor rates, and channel fees change. KitchenMargin treats them as editable inputs rather than universal facts.