Start Avg Unit Cost and End Avg Unit Cost show the average cost per unit of the stock you had on hand at the start and end of the period you selected.

  • Start Avg Unit Cost = starting inventory value ÷ starting quantity
  • End Avg Unit Cost = ending inventory value ÷ ending quantity

If the on-hand quantity on that date is zero or less, the average unit cost shows 0.

The average is worked out for each row of the report. If you group by SKU and warehouse, it is per warehouse. If you group by product, it is the combined value divided by the combined quantity across warehouses.

Where the on-hand value comes from

The value is built from your inventory cost layers, using FIFO (first in, first out) logic, as of each date:

  1. Luminous looks at the cost layers for the SKU in the warehouse. It uses the quantity remaining on each layer, oldest layer first, and ignores layers with nothing remaining.
  2. It values the on-hand quantity by drawing from the oldest layers first, at each layer's cost per unit.
  3. If a layer has a $0 cost, Luminous values those units at the average cost of the SKU's remaining layers that have a non-zero cost. The row is flagged as having zero costs.
  4. If the on-hand quantity is larger than the quantity left on all layers, the extra units are valued at that same average cost.

Fallback cost

If a SKU has no cost layers, or all of its layers are $0, Luminous uses a fallback unit cost instead. It takes the first available of these:

  1. The most recent non-zero cost layer for the SKU, from any warehouse, as of the date
  2. The SKU's weighted base price
  3. The SKU's estimated landed cost

If none of these exist, the cost is 0.

Tips for reading the numbers

  • Start and End costs are calculated separately, each as of its own date. They can differ because of receipts, sales, adjustments and cost changes during the period.
  • An average of 0 usually means there was no stock on that date, or no cost could be found.
  • Because the average is value ÷ quantity, it is a blended figure. It is not the cost of any single layer.

For related reports, see Stock Snapshot Drilldown Reports and Stock Snapshot vs Transaction COGS.