Free BOM Cost Roll-Up Calculator

What does this assembly actually cost to build? Itemize parts, sub-assemblies, and outside processing, and roll the cost up through levels — with the subcontract share made visible. Free, no signup — your BOM stays in your browser.

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BOM Cost Roll-Up

Build your bill of materials and see the true rolled-up cost — parts, sub-assemblies, and outside processing included.

Assembly & Rolled-Up Cost
assemblies
Cost / assembly$8.76
Order total (100 asm)$876.00
Material$561.0064.0%
Labor (internal)$220.0025.1%
Subcontract$95.0010.8%
Routing & Materials operations hold the materials
Operation Material
Operation / PartQty / AsmUOMUnit CostExt / Asm
Op 10
$0.87$2.43
Setup $ Labor $/hr Qty/hr run $0.47 + setup $0.40 = $0.87/pc
$0.84
$0.72
Op 20
$5.38
Type a per-piece cost in Unit Cost — or check Calculate to build it from setup + labor.
$3.70
$0.20
$0.15
Op 21
$0.23$0.23
Setup $ Labor $/hr Qty/hr run $0.23 + setup $0.00 = $0.23/pc
Op 30Subcontract
$0.95
Vendor's quoted price per piece goes in Unit Cost. Add any materials you supply below.

You're rolling up this routing by hand — setup, labor, nested operations, and materials. Fabbric keeps your live BOM & routing linked to quotes, jobs, and POs automatically.

See how Fabbric works →
Rolling up a multi-level BOM

Why assemblies get miscosted

A bill of materials is rarely flat. The harness has leads, the leads have wire and terminals, and somewhere in the middle a vendor crimps or plates or pots something for you. Costing it means rolling up through the levels: each sub-assembly's cost is the sum of its components, multiplied by how many of it the parent uses — and so on up to the top. Do that in a spreadsheet and the errors hide in the multiplication: a quantity fixed at one level but not re-rolled above it, a sub-assembly costed once at last year's wire price and never touched again.

The piece most BOM calculators skip entirely is outside processing. If a subcontractor performs a step — crimp-and-test, anodize, heat treat — that cost belongs in the roll-up exactly like a purchased part, because you can't ship the assembly without it. It also behaves differently: subcontract prices move independently of your material, and their share of the assembly is what quietly erodes margin between quotes. That's why this tool breaks the rolled-up cost out by supply type — Buy, Make, Subcontract — so you can see at a glance how much of the assembly's cost you control and how much rides on vendors.

Once you trust the rolled-up number, it becomes the material cost of the next quote — which is why this tool hands its result straight to the Quote Estimator. Cost the assembly, then price the project.