Make or buy in big batches and each setup is cheap per unit — but the stock sits around costing you to hold. Go small and holding is cheap, but you pay the setup costThe fixed cost of starting a batch, however big: a machine changeover, a purchase order, a deploy, a context switch. It's the same whether the batch is one unit or a thousand. again and again. The economic batch size is where those two pulls balance — and the same maths sizes order quantities, production runs, and how much work to ship at once.
batch size (units) →
| Batch size | Cost / month |
|---|---|
| 245 units | €1,2k +25% |
| 367 units | €1k +4.2% |
| 490 unitsoptimal | €980 the minimum |
| 735 units | €1,1k +8.3% |
| 980 units | €1,2k +25% |
Halve or double the batch and total cost barely moves — being off by a third costs only a few percent. That's the gift of the EOQ curve: you don't need the exact number, just the right ballpark. Tap a row to set it as your batch.