BOQ vs BOM: Bill of Quantities vs Bill of Materials (Comparison Guide)
Teams searching for BOQ vs BOM or the difference between bill of quantities and bill of materials are usually trying to answer one question: which document do I use for pricing and procurement, and which one lists parts for fabrication or supply? This guide answers that in plain language—with a comparison table you can share with non-QS colleagues.
BOQ vs BOM at a glance
| Topic | Bill of quantities (BOQ) | Bill of materials (BOM) |
|---|---|---|
| Primary use | Tendering and contract scope via measured work lines | Manufacturing, assembly, or procurement of components/materials |
| Typical unit | m², m³, m, nr (construction items) | ea, kg, lm (parts and materials) |
| Audience | Contractors, QS, clients comparing bids | Fabricators, buyers, production planners |
| Relation to MTO | Often built on measured quantities from drawings | May roll up from takeoffs or CAD/BIM schedules |
For the full three-way comparison including material takeoff (MTO), see BOQ vs BOM vs material takeoff.
What is a bill of quantities?
A bill of quantities itemizes construction work with quantities so each bidder prices the same scope. Lines usually describe completed work packages (e.g. "150 mm insitu concrete slab") rather than every bolt and bracket.
More context: what is a bill of quantities and the BOQ product overview.
What is a bill of materials?
A bill of materials lists parts, materials, or assemblies—common in manufacturing, prefabrication, and systems procurement (HVAC, joinery, steel packages). It answers "what components do we need?" rather than "what is the measured trade work?"
Product page: Bill of Materials.
Key differences between BOQ and BOM
- Granularity: BOQs group work for pricing; BOMs often go to part level for fabrication or ordering.
- Contract role: BOQs frequently sit in tender packages; BOMs may be internal to subcontractors or suppliers unless specified.
- Updates: BOM revisions track part swaps; BOQ revisions track scope and measurement changes.
Searching bom vs boq usually means you are choosing the right document for your workflow—use BOQ for trade pricing alignment and BOM for component-level build planning.
When you need a BOQ vs a BOM
Use a BOQ when you need comparable tenders for construction work on a project. Use a BOM when you need to order or fabricate a defined kit of parts. Some packages (e.g. modular bathroom pods) may reference both: a BOQ line for installation allowance and a BOM for the pod factory.
How BOQ and BOM work together
On complex jobs, measured quantities from drawings feed both commercial documents (BOQ) and supply chain documents (BOM). Keeping naming and revision control aligned reduces disputes when site quantities diverge from fabrication lists.
For quantity extraction from drawings, see material takeoff and manual vs automated takeoff.
Generate quantity reports from drawings for BOQ and BOM workflows with QtyReport.
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