Bill of Materials Builder

Build a product tree

Link each component to its parent code. The quantity on each row is the amount required by one parent. Requirements multiply along every path and by the requested product quantity. Shared components are consolidated across all paths. For example, two assemblies with four screws each plus three screws directly attached to the product require 2 × 4 + 3 = 11 screws.

Cost and mass

Totals include only leaf components, which have no children. This prevents counting an assembly and its contents twice. Cost and mass entered for assemblies are excluded. Missing values are counted and make the total incomplete rather than silently implying zero. All unit masses use kg. Ensure every unit cost uses the same monetary scale.

Input rules

Paste a tab separated table without a header. A repeated code must retain the same name, unit, cost and mass. Its children apply wherever that code appears. Cycles, missing parents and duplicate links are rejected. Stock deductions, waste allowances, taxes and manufacturing operations are outside the scope.

Consolidate a shared part through two paths

Let example product P contain 3 assemblies A plus 1 part B attached directly. Each assembly A contains 2 parts B. One product therefore needs 3 × 2 + 1 = 7 parts B. Choosing a product quantity of 4 gives 4 × 7 = 28 parts B. Entering a unit cost of 4 currency units and unit mass of 0.2 kg for B gives a cost of 28 × 4 = 112 currency units and mass of 28 × 0.2 = 5.6 kg. These are selected example components only.

Define code B with the same name, unit, price and mass on both links. Do not enter the B requirement inside assemblies again as a separate total at the upper level. The tool expands and consolidates both paths itself. Adding assembly A's price separately to the total would double count. Before ordering, remember that gross requirements are not the amount that existing stock can cover. Resolve missing cost or mass warnings and verify that each unit represents the same quantity throughout the rows. This preliminary calculation does not create a supply schedule or production plan.

Frequently asked questions

How do you calculate bill of materials cost?

For an example 3 products requiring 2 leaf components each at 5 currency units per component, bill of materials cost is 30 currency units. This preliminary calculation multiplies product and component quantities by unit cost, without counting assemblies twice or including stock deductions, waste and tax.