Odoo bill of materials setup: BoMs, operations and work centers in Odoo Manufacturing

A bill of materials, or BoM, is the recipe for a product: which components go in, in what quantities, and which operations turn them into the finished item. In Odoo it is the blueprint behind every manufacturing order, and it also drives kits, subcontracting, cost estimates and replenishment.

A BoM in Odoo has four parts. The Components tab lists materials and quantities. The Operations tab lists the work steps and the work center for each. The Instructions tab holds step-by-step guidance for operators. The Miscellaneous tab carries lead times, batch sizes and readiness rules. You find BoMs under Manufacturing, Products, Bills of Materials, or through the Bill of Materials smart button on any product form.

If you are planning a wider rollout, the Manufacturing app is one piece of a larger design. Our Odoo implementation guide explains how manufacturing fits with Inventory, Purchase and Accounting, and our Odoo manufacturing service covers the configuration work described here.

In any Odoo bill of materials setup, do the foundations first and the BoMs last. A BoM refers to products, units, work centers and costs, so if those are wrong or missing, every BoM built on them inherits the problem. The order below avoids most rework.

Pay close attention to units of measure. If you buy steel by the kilogram and consume it by the meter, or buy fabric by the roll and cut it by the meter, the conversions must exist before the BoM is written. Fixing units after manufacturing orders have run is painful.

• Products and categories: every component and finished item exists, with the right product type, inventory tracking and product category.
• Units of measure: purchase and consumption units set, with conversions defined where they differ.
• Settings: in Manufacturing, Configuration, Settings, enable Work Orders if you will use operations, plus By-Products if you need them.
• Work centers: names, working hours, capacity and hourly costs entered.
• Sub-assembly BoMs: the lowest-level items first.
• Finished product BoMs: built from components and sub-assemblies, with operations and instructions.
• Checks: open the BoM Overview for each finished product and confirm quantities, times and costs.

Odoo offers three BoM types, and the choice changes what happens on the shop floor and in stock. Manufacture this product creates manufacturing orders. Kit sells or ships a set of components as one item without producing anything. Subcontracting has an outside vendor build the product for you.

Kits are often misunderstood. When a kit is sold, it shows as a single line on the quotation and sales order, but the delivery order lists each component. Odoo's documentation recommends setting reordering rules and replenishment at the component level for kits, and notes that stock adjustments cannot be made at kit level. If you need to count and store the assembled item, it is a manufactured product, not a kit.

Add each component with its quantity for the BoM's output quantity, then decide whether the BoM covers one variant or all of them. One BoM can serve every variant of a product: the Apply on Variants column on each component line tells Odoo which variants use it, and a blank value means all of them.

That saves a lot of maintenance. A chair sold in three fabric colors does not need three BoMs. It needs one BoM where the frame, foam and screws apply to every variant and each fabric line applies only to its own color. The Consumed in Operation column links a component to the step that uses it, which matters if you want work to start before every component is in stock.

Products with sub-assemblies need a multilevel BoM. Odoo's documentation advises building from the bottom up: create the BoMs for the lowest-level parts first, then use those parts as components in the next level. Each sub-assembly then has its own lead time, can be stocked, and can be replenished by its own manufacturing orders or reordering rules. The BoM Overview shows the whole tree, with the operations and costs at each level.

In current Odoo versions, the routing is simply the list of operations on the BoM's Operations tab. Each operation names the step, the work center where it happens, its expected duration and whether its cost is based on actual or theoretical time. Each operation belongs to one BoM, but the Copy Existing Operations button lets you reuse an operation from another BoM as an independent copy.

Duration can be fixed, using a default time you enter, or computed from tracked time on a set number of recent work orders. Start with fixed times from your best estimate, then switch busy operations to computed time once you have enough work orders to learn from. The work centers documentation (opens in a new tab) describes each work center field, and the table below shows the ones that matter most for planning and cost.

Add them on the Instructions tab of each operation. Each instruction is saved as a quality control point, and you choose its type: plain instructions, take a picture, register consumed materials, register production, print a label, pass or fail, a measurement within a tolerance, a worksheet or a spreadsheet. You can also attach a PDF that the operator sees at that step.

Keep instructions short and tied to the step where they are needed. A measurement check at the cutting operation, with a failure message telling the operator to raise a quality alert, does more good than a long document attached to the whole BoM. Because these steps live in the Quality app, they need that app installed. Check which edition includes it with our comparison of Odoo Community and Enterprise, and see our Odoo quality service if inspections are central to your process.

Odoo adds the cost of components to the cost of operations. Component cost comes from each component's product cost. Operation cost is the expected duration multiplied by the work center's hourly cost and the per-employee hourly cost. The BoM Overview shows this estimate for any quantity, and greys out costs read directly from product records so you can tell them apart from computed ones.

Each manufacturing order then has two figures: the MO cost, which is the estimate from the BoM, and the real cost, which uses the components actually consumed, the time actually tracked and each employee's own hourly cost from the Employees app. When the two drift apart, either the BoM or the process needs attention.

How that cost reaches your balance sheet depends on the costing method on the product category: standard price, FIFO or average cost. That choice deserves its own discussion, which we cover in Odoo inventory valuation explained.

Treat BoMs as controlled documents. Designs change, suppliers change and components get substituted, so you need a way to update BoMs in bulk and a record of what changed. Odoo provides both.

To replace a component across many products, filter the Bills of Materials list by that component, select the BoMs and use Compare BoMs, or open the component and use its Used In smart button, then change the component on the selected lines in one action. For formal change control, the PLM app adds engineering change orders, which track a proposed change, its approval and a new BoM version, and the Version field on the BoM shows which revision is live.

By-products belong on the BoM too. If production creates a saleable or reusable residue, add it on the By-products tab with an optional cost share, the percentage of production cost assigned to it. The cost shares of all by-products cannot exceed 100. If you run a factory in Pakistan, the UK or the UAE and want your Odoo bill of materials setup designed with your team, see how we work with manufacturing businesses.