What a lot is
Each supplier transfer you record 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.
Cost of goods refines as you add transfers
You don’t have to enter every transfer at once. When you record a supplier transfer — even back-dated — MyProfit automatically recomputes the cost of goods for the sales its lot covers (by purchase date, FIFO). So the profit calculation for those sales gets more accurate the next time you open the report — with no full rebuild. Report accuracy grows gradually, as you add more transfers.
Why a balance can go negative
The balance in MyProfit is a calculation: what you’ve recorded receiving, minus everything the marketplace sold and wrote off. If more was sold than you’ve entered, the balance goes negative. It isn’t a separate “error” record to clean up — just a computed shortfall.
This happens for two reasons:
- A sale synced before its receipt. The product is already sold, but you haven’t entered the transfer for it yet — an ordinary ordering gap, and temporary.
- You were trading before you started recording purchases in MyProfit. The system then sees every sale but only the purchases you’ve entered, so the negative can be sizable — especially on the warehouse orders ship from («Фулфилмент» by default). That’s an honest gap between recorded purchases and sales, not a fault.
Either way, a negative balance is usually not a bug, but a signal that a needed receipt hasn’t been entered yet.
What to do
Record the missing supplier transfer — add supplies and returns — or enter a correction (opening balance): a positive entry on the right warehouse with the real date and, if you know it, the purchase cost (so cost of goods is computed just like from an invoice). You can set the real date, even a past one: MyProfit recomputes the history itself and the balance comes into line. There’s no separate “restore” step to run — history is computed continuously.
Related
- Add supplies and returns — how to record the transfer that closes the shortage.
- Stock: a unified view by article — where the balance per product is shown.
- How profit is calculated — where the refined cost of goods lands.