Choose Your Cost Tracking Method
Bookkeep always tracks weighted average cost (WAC) for every variant. The setting on this page decides one thing: which number gets written to Shopify's cost per item when a receipt commits, your WAC or the last cost received. It lives in Settings → Purchase orders under Shopify cost push on receipt.
Where costs come from
Bookkeep knows a cost for an item from two sources only:
- Receipts. Receiving a line on a Bookkeep purchase order records its landed cost and blends it into the item's WAC.
- Opening cost. A seed loaded by import or by Bookkeep Support, used as the starting WAC before any Bookkeep receipt. See Seed your opening costs.
Bookkeep does not read Shopify's cost per item. An item that has never been received or seeded in Bookkeep has no cost here, whatever Shopify shows for it.
What the Inventory on Hand report shows. The report under Reports always prices each item at its WAC, regardless of this setting. Items with no recorded cost show a blank cost and value and are counted under Unvalued variants. To fill them in, receive them on a purchase order or seed an opening cost.
The two methods
Weighted average cost (WAC): Shopify gets the blended landed cost of everything you have received, weighted by quantity. This is the default. See How Weighted Average Cost Works for the mechanics.
Last cost received: Shopify gets the unit cost on the receipt line you just received, before allocated fees and discounts. Whatever you paid last time becomes Shopify's cost for every unit on hand.
Which one fits your store
Last cost tells you what an item costs to replace today. WAC tells you what you actually paid for what is sitting on the shelf.
Last cost received works when supplier pricing is stable, you buy each item from one source, and you want Shopify to carry today's replacement price. It is the easier number to explain, because it traces back to one invoice.
Weighted average cost fits when prices move, you buy the same item from several suppliers, or freight varies between shipments. It is the conventional method for inventory valuation, so it is usually what your accountant expects.
WAC uses the landed cost of each receipt: unit price, plus allocated fees like freight or duty, minus allocated discounts. Set up fee types under Settings → Landed cost fees, each with a default allocation method, by quantity or by value. Allocation changes your numbers more than you might expect, see how allocation affects weighted average cost and Configure Fees and Discounts.
Switching between the two
You can change the setting at any time. Switching changes nothing in Bookkeep: the cost ledger, WAC, and the Inventory on Hand report are the same under both settings. Only Shopify's cost per item is affected, and only for items received after the switch.
- Switching does not push anything. The setting is read when a receipt commits. Flipping it writes nothing to Shopify.
- Each item carries its last pushed cost until its next receipt. Switch from last cost to WAC and an item received under last cost keeps that cost in Shopify until you receive it again.
- Voids and cost corrections use the current setting, not the one in force when the receipt was made.
One item, received twice, with the setting changed in between:
| Step | Setting | Bookkeep WAC | Shopify cost per item |
|---|---|---|---|
| Receive 10 at $10.00 | WAC | $10.00 | $10.00 |
| Switch to last cost received | $10.00 | $10.00 | |
| Receive 10 at $14.00 | Last cost received | $12.00 | $14.00 |
| Switch back to WAC | $12.00 | $14.00 | |
| Receive 10 at $14.00 | WAC | $12.67 | $12.67 |
Between the third and fifth steps, Bookkeep values the item at $12.00 and Shopify at $14.00. Shopify's own profit and cost reports use its cost per item, so they diverge from Bookkeep's until the next receipt.
What gets recorded
Every cost push to Shopify is logged with the value sent, which method produced it, and whether it succeeded, alongside supplier cost history and the landed cost allocations on each receipt. You can review all of it from the purchase order or from the product variant.
If a receipt was entered wrong, it gets repaired rather than erased, see Fix a Receipt: Voids and Cost Corrections.