What is a bill of materials (BOM)?

A bill of materials is a structured list of parts, materials, and subassemblies required to build one finished product. It usually includes part numbers, quantities per unit, units of measure, and often unit costs and suppliers.

What is a multi-level BOM?

A multi-level BOM nests subassemblies under the finished product. Level 0 is the finished good, level 1 components or subassemblies, level 2 parts inside those subassemblies, and so on. This builder supports levels 0-5 for planning.

Does this BOM builder store my product data?

No. Drafts stay in your browser with localStorage. Nothing is sent to a server. You can clear the draft anytime with Reset.

Is this an MRP or inventory system?

No. This is a free planning workbench for small manufacturers and makers. It does not track on-hand inventory, work-in-process, or purchasing automation.

Bill of materials template

Build the parts list before you buy or assemble.

Create a free multi-level bill of materials with quantities, unit costs, scrap uplift, vendor lead times, and exportable cost rollups. Runs in your browser — no signup.

No signup
Saved locally
Copy, CSV, TXT, print

BOM workbenchDraft ready

1. Product header

Name the finished good, revision, and how many units you plan to build.

Product name

SKU / item number

Revision

BOM type

Units to build

Owner / planner

BOM date

Status

Product notes

This page is a planning aid for parts lists and rough product cost — not MRP, inventory control, tax, or accounting advice. Confirm purchase specs and supplier terms before buying.

2. BOM lines

Add components and subassemblies. Level indents the hierarchy (0 = top-level under the product). Extended cost = qty per unit × unit cost.

3. Scrap and labor uplift

Optional planning uplifts applied to the rolled-up material cost per finished unit.

Scrap / yield loss %

Labor cost per unit $

Other overhead per unit $

How a bill of materials works

A bill of materials is the parts recipe for one finished unit. Before you buy inventory or start assembly, someone should know which components are required, how many of each go into one unit, what they cost, who supplies them, and how long they take to arrive.

This builder is structured instead of blank. You capture the product header, nest multi-level lines, roll up unit and batch cost with optional scrap and labor, run a completeness audit, and export plain text plus CSV. Drafts stay in your browser until you reset them.

Indent the hierarchy

Use higher levels for subassemblies so buyers and builders see what sits inside what — not a flat grocery list.

Cost before you buy

Qty times unit cost makes supplier quotes comparable and shows what scrap does to true material cost.

Track revision honestly

Mark Draft to In Review to Released so the shop floor builds from the version you intend.

Formula and assumptions

Line extended (per finished unit) = quantity per unit times unit cost. Material cost per unit = sum of all line extended amounts. Scrap uplift per unit = material times (scrap percent divided by 100). Total cost per unit = material + scrap + labor per unit + overhead per unit. Batch totals multiply the per-unit figures by units to build.

Formula: total cost / unit = sum(qty times unit cost) times (1 + scrap%/100) + labor/unit + overhead/unit.

Scrap, labor, and overhead are optional planning inputs. Confirm inventory valuation and tax treatment with your own advisor. This page is not legal, tax, or accounting advice.

When to use this template

Use a BOM for product launches, private-label kits, light manufacturing, repair kits, assembly quotes, and any build where parts and cost must stay aligned. It fits makers, CPG assemblers, hardware startups, and shops graduating from sticky notes to a real parts list.

Do not treat a draft BOM as a substitute for an MRP system, CAD PLM export, or controlled engineering change process. After release, keep the export with drawings, PO history, and revision notes.

Related tools on this site: the Purchase Order Builder to buy the parts, the Work Order Builder to authorize assembly labor, the Vendor Scorecard Builder to compare suppliers, and the Pro Forma Invoice Builder for customer quotes.

Example: insulated flask assembly

Northline Goods is releasing Trail Flask 20oz. The BOM includes the vessel body, lid assembly (with gasket and seal as lower-level parts), powder-coat service, sleeve, and packaging. Use Load example above to inspect multi-level lines, scrap uplift, unit and batch cost, and the shop-ready preview.

Frequently asked questions

What should a BOM include?

Product name and SKU, revision, status, each part number and description, quantity per finished unit, unit of measure, unit cost when known, vendor and lead time when useful, and notes for alternates or QC checks.

How is a BOM different from a purchase order?

A BOM lists what is required to build one unit. A purchase order authorizes buying specific quantities from a vendor. You often generate POs from a BOM times the build quantity.

Can I model multi-level subassemblies?

Yes. Set Level on each line (0-5). Higher levels nest under the product hierarchy for planning clarity. Cost still rolls up from every line.

Where is my BOM data stored?

Only in your browser via localStorage. Nothing is uploaded to Useful Business Tools servers. Use Reset to clear the local draft.