What Is Cost Roll-Up?
Also known as: cost rollup, standard cost roll up, BOM cost rollup
Definition
A cost roll-up calculates the cost of manufactured items by summing the cost of purchased components, routing labor, machine time and overhead from the lowest BOM level up to the finished product. The result is usually saved as standard cost.
Cost Roll-Up Explained
The roll-up starts at the bottom of the bill of materials. Purchased and raw items take their cost from a purchase price, average cost or a manually set standard. Each manufactured subassembly then adds the cost of its components, plus the labor, setup and overhead from its routing, and passes that total to the next level up until the finished item is costed.
Inputs must be right for the result to mean anything: accurate BOM quantities and scrap factors, routing run times and setup times, work center rates, and current component costs. Yield or scrap assumptions inflate the roll-up, and a phantom BOM is rolled through as if its components belong to the parent.
Every major ERP has a roll-up routine. SAP runs a standard cost estimate with CK11N for one material or CK40N for the marking and release workflow. Dynamics 365 Business Central has a Roll Up Standard Cost batch job. NetSuite lets you update standard cost from a roll-up of components and routing on the item record or through standard cost revaluation. SyteLine and Infor LN provide cost calculation routines driven by the item cost type and cost components.
A common practice is to run a trial roll-up, compare it with the current standard, review the largest changes, and only then release the new standard and post the inventory revaluation.
Why It Matters
- It sets the standard cost that inventory valuation and margin reports depend on.
- It exposes BOM and routing errors, because absurd rolled costs usually trace to bad quantities, units or rates.
- Annual or quarterly roll-ups keep standard cost close to the real cost of materials and labor.
- Costing a proposed engineering change before release shows its price impact in advance.
In Practice
A pump assembly BOM has components costing 180, a subassembly rolled to 95, and routing time of 1.5 hours at a 60 combined labor and overhead rate, which is 90. The roll-up gives 180 + 95 + 90 = 365. If a casting price rises 10 percent and costs 40, the next roll-up would add 4 per unit and flag a purchase price variance until standards are updated.
Frequently Asked Questions
How often should I run a cost roll-up?
Most manufacturers do it at least annually, and many quarterly. More frequent roll-ups mean more revaluation entries, so teams balance accuracy with workload.
Does a roll-up change inventory value?
Releasing a new standard cost revalues on-hand inventory and WIP to the new cost, which posts a revaluation entry to the general ledger.
Why does my rolled cost look wrong?
Typical causes are wrong unit of measure on BOM lines, missing or inflated routing times, outdated work center rates, or components that still have no cost.
Related Terms
Standard Cost
Standard cost is a predetermined per-unit cost for material, labor, and overhead, set in advance and used to value inventory and transactions. Differences between standard and actual are captured as variances that isolate where cost deviated.
BOM (Bill of Materials)
A BOM (bill of materials) is the structured, hierarchical list of components, sub-assemblies, and quantities required to produce one unit of a parent item, and it is the primary input MRP explodes to calculate material requirements.
Routing
A routing is the ERP record that defines the ordered sequence of operations required to manufacture an item, specifying for each step the work center or machine, setup time, run time per unit, move and queue time, and any outside processing.
Overhead Absorption (Applied Overhead)
Overhead absorption is the process of charging indirect manufacturing costs, such as factory rent, utilities and supervision, to products or jobs using a predetermined rate based on labor hours, machine hours or another base.
WIP (Work in Process)
WIP (Work in Process) is inventory that has been released to production and has begun conversion but is not yet a finished good. It includes partially machined parts, subassemblies, and material sitting in queue between operations.
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