Weighted average cost
Every ingredient in BatchDash carries one unit cost: its weighted average cost, or WAC. It answers a simple question: across everything currently on the shelf, what did one kilogram of this actually cost me? Formulas, runs and stock values all price from it.
The “weighted” part is the point. Prices move between purchases, and a plain average of the two prices would ignore how much you bought at each. WAC weights each delivery by its quantity, so a big cheap crate counts for more than a small expensive top-up.
A worked example
Section titled “A worked example”Your chili farm delivers 10 kg of habaneros at €12.00/kg, then two weeks later 5 kg at €15.00/kg.
| Delivery | Quantity | Unit price | Value |
|---|---|---|---|
| First | 10 kg | €12.00/kg | €120.00 |
| Second | 5 kg | €15.00/kg | €75.00 |
| On hand | 15 kg | €195.00 |
WAC = €195.00 ÷ 15 kg = €13.00/kg. The midpoint of the two prices, €13.50, would be wrong: the cheaper delivery was twice the size, so it pulls the average down.
Use 6 kg in a batch and the batch is charged 6 × €13.00 = €78.00. The remaining 9 kg still cost €13.00/kg; consumption never changes the unit cost, only the quantity.
What moves it, what doesn’t
Section titled “What moves it, what doesn’t”Moves it: costed deliveries. Logging a delivery against a vendor offer, or receiving a purchase-order line, folds the new value into the average. Order receipts use the landed cost: delivery and platform fees are spread across the lines first, so the WAC reflects what the ingredient cost to get onto your shelf.
Doesn’t move it: using stock in a run, losses, spoilage, count corrections. These change how much you have, valued at the current WAC, but not what each unit cost.
One practical consequence: an ingredient with stock but no costed delivery can’t be valued, and any formula using it can’t be costed. The ingredient card flags this; the fix is a delivery with a price, as shown in set up your inventory.
Where you see it
Section titled “Where you see it”The inventory list shows each ingredient’s WAC in the Avg cost column and multiplies it out into the stock Value. Formula cost panels price every line from it. Runs consume at it. When you look at an ingredient’s card, the price history puts the current WAC next to what vendors are quoting today, which is how you notice the market drifting away from your average.
WAC is deliberately steady. It won’t jump because one vendor had a bad week, and it keeps batch costs comparable across months. When you want the sharp edge of the latest quote instead, that’s what vendor offers are for.