Bill Of Materials

At the heart of the Manufacturing system is the Bill of Materials (BOM). The BOM is a list of all materials (either bought or made) and operations that go into a finished product or sub-Item. In ERPNext, the component could have its own BOM hence forming a tree of Items with multiple levels.

To make accurate Purchase Requests, you must always maintain correct BOMs. To make a new BOM:

Manufacturing > Bill of Materials > New BOM


  • To add Operations select 'With Operation'. The Operations table shall appear.


  • Select the Item for which you want to make the BOM.
  • Check 'Inspection Required' to make the 'Quality Inspection' mandatory for raw materials and the finished goods.
  • Add the operations that you have to go through to make that particular Item in the “Operations” table. For each operation, you will be asked to enter a Workstation. You must create new Workstations as and when necessary.
  • Workstations are defined only for product costing and Work Order Operations scheduling purposes not inventory.
  • Inventory is tracked in Warehouses not Workstations.

Costing of a BOM

  • The Costing section in BOM gives an approximate cost of producing the Item.

  • Add the list of Items you require for each operation, with its quantity. This Item could be a purchased Item or a sub-assembly with its own BOM. If the row Item is a manufactured Item and has multiple BOMs, select the appropriate BOM. You can also define if a part of the Item goes into scrap.


  • This cost can be updated on by using the 'Update Cost' button.

Update Cost

  • User can select the currency in the BOM
  • System calculates the costing based on the price list currency

Update Cost

Materials Required(exploded)

This table lists down all the Material required for the Item to be Manufactured. It also fetches sub-assemblies along with the quantity.

Exploded Section

Next: Work Order