How a job costs out
The make-to-order tour built robots. This flow follows the money those jobs spend. As a job is worked, Carbon accumulates its cost (materials consumed, plus labor, machine, and overhead time) into , then releases that cost into finished-goods inventory when the job completes. Every figure here is grounded in real ledger postings, so it's worth being precise about what posts, when, and to which account.
Accounting is a switch
The first thing to know is that costing is gated. A company setting, accounting enabled, is off by default. With it off, the physical world still moves: the item ledger records quantities, job and operation statuses advance, material gets issued. But no general-ledger entries and no cost layers are written. Turn it on and the same operations also post money.
Quantities always move; money only moves when accounting is on.
Receiving, issuing, completing: the physical and status changes happen regardless. The GL postings described in this flow are written only when accounting is enabled for the company, so a shop can run operationally before it runs its books.
Cost lands in WIP
As the job runs, cost flows into its work-in-process. Two streams feed it.
Material. When a job consumes a part ( to an operation, or at completion), Carbon moves that part's cost out of inventory and into WIP. The ledger entry is a debit to the work-in-process account and a credit to inventory, tagged Job Consumption.
Labor, machine, and overhead. Every production event a worker or machine logs carries a duration. Carbon prices it against the work center's rates and posts it in real time: a debit to WIP, a credit to an absorption account, tagged Production Event. Labor and machine time each post at their own rate (hours times the rate); if the work center also carries an overhead rate, the event books a second pair, a debit to WIP and a credit to an overhead-absorption account, at that rate. All three rates come from the , not from the operation's estimate.
WIP collects real material plus labor, machine, and overhead time.
WIP is the sum of consumed material and the priced production events. Each event posts labor and machine at the work center's rates, and when the work center has an overhead rate, that too is absorbed into WIP alongside the time, gated on the overhead-absorption account being configured. WIP is real material plus real time, not a standard estimate.
Issued or backflushed
That material reaches WIP one of two ways, and the difference is when. Issuing pushes a part to an operation as the work happens, the same move the picking list drives when it stages material to the line. Backflushing waits for the finish: when the job completes, Carbon consumes whatever the method called for that wasn't already issued, in a single sweep.
The posting is identical either way (cost out of inventory, into WIP), so the choice is about floor discipline, not accounting. Issue as you go when you need tight control over what's consumed; lean on backflush for the routine material you'd rather not hand-count.
Scrapped material is consumed cost, too.
and are recorded as their own production quantities, but scrapping a tracked part posts the same consumption: out of inventory, into the job's WIP. There's no separate scrap account; the cost of what you ruined rides along in the job until it settles at close.
WIP isn't a table
Here's the part most ERPs hide. In Carbon, work-in-process is not a column or a table you can read off a job. It's a balance in the general ledger, the sum of every posting against the work-in-process account that carries this job's id. A job's WIP is a query, not a field.
The cost itself lives in the cost ledger, where each inbound entry opens a layer with a remaining quantity. How a consumed part is priced depends on the item's : FIFO or LIFO walk the open layers, Average uses the running unit cost, Standard uses the standard cost. That choice changes the amount of the WIP entry, but the shape never changes: cost in from inventory, cost out to finished goods.
A layer is a cost-ledger row with quantity left on it.
There is no separate cost-layer table. Open layers are cost-ledger rows that still have remaining quantity. Consuming walks those layers by date for FIFO or LIFO; the costing method only decides which cost a consumption picks up, never whether WIP is tracked.