Bill of Materials — The Ultimate Guide for Small Manufacturers

Here’s something most makers don’t realise until they’ve been at it a while: if you make anything from ingredients or components, you already have a Bill of Materials. You just haven’t written it down yet.

That mental model — “BOMs are for factories, not me” — is exactly what keeps small manufacturers stuck in the spreadsheet loop. The truth is, a BOM is just a formalised list of what goes into your product. Write that list down, add quantities and costs, and suddenly you can price confidently, order accurately, and scale without chaos.

This guide covers everything you need to know — what a BOM is, why it matters, how to create one, and which software handles BOMs well for small-batch makers in 2026.

What is a Bill of Materials?

A Bill of Materials (also written as BOM or BoM) is a comprehensive list of every component, material, and sub-assembly needed to manufacture a finished product — along with the quantity, unit cost, and source for each item.

It’s the single source of truth for what a product is made of. And because it captures costs at the ingredient level, it’s also the foundation for accurate COGS calculation and confident pricing.

Here’s a simple example. If you were making a wooden chair, your BOM might look like this:

• 4 × wooden legs
• 2 × armrests
• 1 × seat
• 1 × backrest
• 12 × screws
• 8 × bolts
• 10ml wood finish

That’s the starting point. From there, you’d add unit costs, unit of measurement (ml, item, g), and vendor information — turning a simple list into a tool that drives your whole production process.

Benefits of Using a Bill of Materials

The importance of a BOM in inventory management and manufacturing processes cannot be overstated. A well-maintained BOM is truly the cornerstone of effective resource planning in manufacturing inventory management.

A BOM provides a clear, step-by-step guide for assembling the final product. It ensures every component is accounted for, reducing production errors and improving overall efficiency. And because it’s anchored to real costs, it means every pricing decision you make is grounded in fact — not guesswork.

Here are the key advantages:

• Enhanced production efficiency: A well-planned BOM simplifies production and reduces errors. Pairing it with a production scheduling system lets you sequence runs, manage capacity, and prevent bottlenecks before they happen.
• Reduced costs: Knowing exactly what components you need means you can optimise inventory levels — avoid overstocking, avoid stockouts, save on storage costs, and stop losing sales.
• Consistent product quality: Every product follows the same assembly process, which means consistent quality at any scale.
• Scalability: As you grow and your products get more complex, a robust BOM system means you can scale without compromising quality.
• Accurate cost estimation: A detailed BOM helps you accurately estimate the cost of goods manufactured by capturing all materials and their real costs.
• Streamlined procurement: Your purchasing becomes predictable — you know exactly what to order and when. A purchase order system can automate ordering based on what your BOM requires.
• Improved inventory control: When you know exactly what goes into each product, forecasting becomes reliable and reorder timing becomes obvious.

Types of Bill of Materials

Multiple types of BOM exist, depending on the level of detail required and your specific needs. Here’s a quick rundown:

• Engineering BOM: The most detailed type, including part numbers, quantities, and assembly instructions. The APICS Dictionary defines this as the design record for an end item as designed.
• Manufacturing BOM: Focuses on the materials needed for production, including details like vendor names and lead times. This is the type most small-batch makers work with day-to-day.
• Sales BOM: A simplified version used for sales purposes — highlights key components and features for customers.
• Modular BOM: Used for products with interchangeable components, allowing for modular assembly. Useful if you make product variants that share most ingredients.
• Kitting BOM: Groups together materials needed to manufacture a particular product; simplifies the production process for bundled or gift-set products.

The Key Components of a Bill of Materials

Although there’s some variability in what a BOM contains, most include:

• Part numbers / SKU numbers: Unique identifiers for each raw material in the BOM — crucial for accurate inventory management.
• Description: A brief description of the component so it’s easily recognisable.
• Quantity: The number of units required for each production run.
• Unit of Measurement: The unit in which the component is measured (e.g., pieces, metres, grams, ml).
• Vendor information: Preferred supplier details. A purchase order system can then automate ordering against these specs.
• Unit cost: The cost of an individual unit, including any associated expenses like shipping or handling.

When creating BOMs for multi-staged production processes, it’s also important to include sub-assemblies, work-in-progress (WIP) items, and finished products. This level of detail keeps production flowing smoothly across all stages.

Read more: Bill of Materials: Real World Examples

Tips for Maintaining an Effective Bill of Materials

• Keep it updated: Review and update your BOMs regularly to reflect any changes in product design or materials.
• Use a standardised format: A consistent format makes it easy for everyone on your team to read and use. Software enforces this automatically. For batch-based production, linking your BOM to batch tracking records makes it easy to verify that every production run used the correct materials in the right quantities.
• Integrate with inventory management software: Software like Craftybase significantly speeds up BOM creation and improves production accuracy. When your BOM is connected to your inventory, material deductions happen automatically — no manual counting required.
• Use manufacturing travelers for complex production: If your products go through multiple workstations or production stages, manufacturing travelers pair well with BOMs by tracking work-in-progress at each step.

How to Create a Bill of Materials

Creating a BOM can feel like a lot of upfront work — which is exactly why most small makers put it off until they’re drowning in orders. Don’t wait.

Here are the three main approaches:

• Spreadsheets: Excel or Google Sheets are the most common starting point and work for BOM templates. Easy to customise but hard to maintain — especially as your product range grows and you need to track costs dynamically.
• Inventory management or MRP software:Inventory management software with bill of materials like Craftybase integrates all necessary data in one place — materials, costs, production runs, and purchase orders. When you record a production run, your BOM automatically deducts the correct quantities from stock. Small manufacturers who aren’t ready for a full ERP often find that a materials requirements planning (MRP) approach is a better fit — lighter weight, but still BOM-driven.
• ERP systems: For larger businesses requiring complex BOMs across multiple sites or currencies. Usually overkill for small-batch makers, and priced accordingly.

Read more: How to create a Bill of Materials (BoM) in 7 easy steps

BOM Software Comparison: Which Tool Is Right for Small Manufacturers? (2026)

Once you’re ready to move beyond spreadsheets, the question becomes which tool handles BOMs well for small manufacturers. Here’s how the main options compare:

For small-batch makers — soap, candles, cosmetics, food, jewellery — Craftybase is designed specifically around the recipe/BOM workflow. Costs are tracked at the raw material level, deducted automatically on each production run, and rolled up into accurate COGS reports for tax time.

inFlow and Cin7 Core are solid for product-based businesses that have outgrown spreadsheets but need more traditional warehouse management features. They’re better fits once you’re managing a team and multiple warehouse locations.

For a deeper comparison across seven platforms, see our best inventory management systems for small manufacturers guide.

Frequently Asked Questions

Conclusion

A Bill of Materials is the most under-utilised tool in small manufacturing. Most makers already have one — in their head, in a notebook, or buried in a spreadsheet — but haven’t formalised it in a way that drives their production, costing, and inventory decisions.

When you do, everything else gets easier. Pricing is based on real numbers. Reorder points are calculated, not guessed. COGS is accurate at tax time. And production runs flow smoothly because every ingredient is accounted for before you start.

If you make jewelry, BOMs are particularly powerful given the number of components that go into each piece — our guide to jewelry inventory software covers which tools handle multi-component BOMs well for makers working with stones, wire, and findings. And if you’re ready to compare BOM-aware manufacturing platforms across the board, our best manufacturing software for small business guide compares seven tools on exactly this dimension.