What a lot is
Each applied supplier transfer creates a lot — a separate batch with its own date and unit purchase cost. The same product can arrive in several lots at different prices, and MyProfit keeps each one separately.
FIFO: oldest consumed first
When a product is sold, MyProfit consumes units from the lots first-in, first-out (FIFO): the earliest lot is used up first, then the next. That is exactly what makes per-SKU cost of goods accurate — a sale takes the price the product was actually bought at, not an average.
Why a balance can go negative
Sometimes the balance for a product goes negative. A shortage lot appears — a lot with a negative quantity. It shows up when a sale synced before you recorded the transfer for that product: the sale is already in, but the transfer isn’t in MyProfit yet.
Such a lot is temporary. It closes by itself once you record the missing supplier transfer — the negative quantity is offset by the new lot. So a negative balance is usually not a bug, but a signal that the transfer hasn’t been entered yet.
What to do
Record the missing supplier transfer — add transfers. Once it’s applied, the shortage lot closes and the balance evens out.
Related
- Add transfers — how to record the transfer that closes the shortage.
- Stock: a unified view by article — where the balance per product is shown.