Explainer · Production

Multi-Level BOM Explained for MSMEs (2026)

Updated 2026 · ~6 min read

If you manufacture anything with sub-assemblies, a single-level parts list is not enough. You need a multi-level Bill of Materials (BOM). Done right, a multi-level BOM gives you accurate costing, clean purchase planning and reliable stock. This explainer breaks it down in plain language.

In one line: a multi-level BOM is a “recipe of recipes” — it lists not just the raw materials, but the sub-assemblies and their materials too, level by level.

What is a BOM?

A Bill of Materials lists everything needed to make a product — raw materials, components and quantities. A single-level BOM lists the direct inputs of one product. A multi-level BOM also breaks down each sub-assembly into its own inputs, creating a tree from the finished product down to raw materials.

A simple example

Imagine a product that is assembled from two sub-assemblies, and each sub-assembly is made from raw materials:

Level	Item	Made from
0	Finished Product	Sub-assembly A + Sub-assembly B
1	Sub-assembly A	Raw material 1 + Raw material 2
1	Sub-assembly B	Raw material 3 + Raw material 4

With this structure, the system knows exactly how much of every raw material a finished-product order needs — all the way down.

Why multi-level BOM matters for MSMEs

Accurate costing — roll up costs from raw material through each sub-assembly to the finished product.
Better purchasing — know exactly what to buy for a given production plan.
Reliable stock — consume materials correctly at each stage.
Real margins — when material prices change, costs update at every level.
Job work fit — sub-assemblies can be made in-house or sent out for job work.

How LastingERP handles multi-level BOM

LastingERP supports multi-level BOM with stage-wise production tracking, so material and output are recorded at each level, costs roll up automatically, and purchasing and stock stay accurate — whether a sub-assembly is made in-house or through job work.

Frequently asked questions

What is a multi-level BOM?

A multi-level Bill of Materials breaks a product down through its sub-assemblies to raw materials, level by level. It shows not just the direct inputs but what each sub-assembly is made from.

Why do manufacturers need multi-level BOM?

Products with sub-assemblies need it for accurate costing, correct purchasing and reliable stock. A single-level list cannot capture how sub-assemblies consume materials.

Does multi-level BOM help with costing?

Yes. Costs roll up from raw material through each sub-assembly to the finished product, and update automatically when input prices change, giving you true margins.

Can sub-assemblies be job-worked?

Yes. A sub-assembly in a multi-level BOM can be produced in-house or sent out for job work, and the ERP tracks it either way.

See multi-level BOM in action

Book a demo and watch costs roll up level by level.

Book a Free Demo +91-9888886589

General educational information to help manufacturers understand BOM concepts. Verify specifics for your process during a demo.