- Cost of goods sold = opening inventory + net purchases − closing inventory.
- Prime cost = cost of goods sold + labour cost.
- Prime cost % = prime cost ÷ net sales × 100.
- Difference from target = prime cost − (net sales × target ÷ 100).
Illustrative example: net sales of €20,000, opening inventory of €4,000, purchases of €6,000, closing inventory of €3,000 and labour of €6,000 give a product cost of €7,000 and prime cost of €13,000: 65%. The remaining €7,000 must cover other expenses and profit or loss. With your own target of 60%, costs are €1,000 above target.
Purchases are not the same as consumption: that is why both inventories are included. Without a reliable stock count, the result is also an estimate. This free resource does not calculate recipes or replace accounting close procedures or professional advice.