If you have ever stared at an empty bank account on Monday morning after a sold-out craft fair, you know the sinking feeling. You sold every candle, ring, or pastry on your table, yet somehow the cash left in your drawer barely covers your next supply run.
The culprit almost always traces back to a missing production discipline: confusing a kitchen recipe with a Bill of Materials (BOM). A recipe tells your hands how to combine ingredients; a Bill of Materials tells your business what it actually costs to manufacture a sellable unit down to the penny.
When makers calculate costs in their heads, they count the obvious raw supplies—the 155g of Golden 464 soy wax or the 18ga sterling silver wire. But they forget the 4-cent wick sticker, the warning label, the kraft mailing box, the 5% wax cling left inside the pouring pitcher, and the tissue wrap. Those uncounted line items silently eat 15% to 25% of your net profit on every single order.
How to make a Bill of Materials (BOM)?
Scrap Multiplier (typically 3% to 10%) to absorb unavoidable workshop waste.| Component Layer | Craft Example | Cost Factor |
|---|---|---|
| Raw Materials | Golden 464 Soy Wax (155g) | $0.64 base cost + 5% pot cling buffer |
| Hardware & Findings | ECO 10 Wick & Sustainer Tab | $0.18 per assembly |
| Sub-Assemblies | Master-Batch Fragrance Blend | 15g pre-weighed botanical formulation |
| Packaging & Labels | 8 oz Amber Jar + Lid + Warning Label | $2.35 combined packaging vessel |
| Scrap Multiplier | 1.05x (5% workshop loss factor) | Absorbs spillage, trimmings, and testing |
* Calculated based on standard batch production benchmarks. Direct artisan labor and studio overhead are added to the final adjusted BOM total to determine complete Cost of Goods Sold (COGS).
The 4 Anatomy Layers of a Maker BOM
Engineers at aerospace companies build BOMs with thousands of sub-assemblies. In an artisan studio or small-batch kitchen, you do not need enterprise ERP software. You only need to organize your materials into four disciplined layers:
Substances that transform or melt during batch production: soy wax flakes, lye, olive oil, King Arthur bread flour, or sheet clay. These are bought in bulk cases or bags and measured by weight (grams/ounces) or volume (mL).
Discrete physical items joined during assembly: candle wick tabs, glue dots, earring posts, sterling jump rings, zipper pulls, and rivets. These are almost always purchased by count (pieces, gross, packs).
Intermediate parts prepared in advance: a master-batched fragrance blend, pre-cut sterling bezel strips, or pre-glued wick-and-tab sets. Treating them as sub-assemblies keeps large production runs organized.
Everything the customer touches before reaching the product: glass jars, metal lids, cigar band paper sleeves, bakery display boxes, caution warning stickers, and thank-you cards.
The Phantom Cost Trap
Single-Level vs. Multi-Level BOMs: Demystified for Beginners
When researching Bill of Materials templates, you will encounter the terms single-level and multi-level (also known as indented BOMs). Here is what that means on your studio workbench without corporate jargon:
Single-Level BOM (Flat List)
A flat list where every single component goes directly into the final item in one step. For example, melting wax, adding oil, inserting a wick, and closing the jar. It is ideal for simple products with no prep steps.
Multi-Level BOM (Sub-Assemblies)
A hierarchical list where one line item is itself built from earlier materials. For example, in jewelry making, a Bezel Setting Sub-Assembly requires 18ga wire, bezel strip, and solder. Once completed, 4 of those sub-assemblies are mounted onto a cuff bracelet alongside gemstones and packaging.
If you are just getting started, start with a flat single-level BOM. As your batch sizes grow past 50 units, group pre-prepped components into sub-assemblies so you can track prep-day inventory separately from market assembly days.
The Math: Converting Bulk Invoices into Grams and Inches
Suppliers do not sell you 155 grams of soy wax or 2.8 inches of sterling wire. They sell you a 45 lb case of Golden 464 wax for \$84.00, or a 50-foot coil of 18ga round wire for \$45.00. The primary job of your BOM is calculating the exact unit conversion.
The Unit Conversion Formula
Unit Material Cost = (Bulk Invoice Price / Bulk Package Quantity) × Usage QuantityEnsure your package quantity and usage quantity use identical units (convert pounds to grams, or feet to inches) before calculating.
Let’s walk through a real candle studio calculation:
- Bulk Purchase: 45 lb box of Golden 464 wax = \$84.00 total invoice.
- Unit Conversion: 45 lbs × 453.592 grams/lb = 20,411.6 grams.
- Cost per Gram: \$84.00 ÷ 20,411.6g =
$0.004115 per gram. - Usage per Candle: 155 grams of wax $\times \$0.004115 = $0.638 (approx. $0.64).
Now repeat this across every component: fragrance oil, wick, jar, label, and box. Summing these gives your raw, unadjusted BOM total.
The Scrap Multiplier: Don't Let Trimmings Eat Your Wage
In a theoretical spreadsheet, 100% of the materials you buy end up in a customer's hands. In a real workshop, reality bites:
- Candle wax coats the side of the melting pitcher and thermometer (3% to 6% pot cling).
- Sterling silver wire gets nipped off with flush cutters and ground into bench dust (5% to 10% scrap loss).
- Cold process soap loaves lose 10% to 12% of their wet weight during curing water evaporation, plus beveling scrap from end cuts.
- Royal icing cookies occasionally break or smudge during packaging (5% defect scrap).
The Scrap Multiplier Rule
If your raw materials cost \$4.20 per unit and your workshop experiences 7% waste, multiply \$4.20 by 1.07 = $4.49 adjusted material cost.
Interactive Bill of Materials Costing Playground
Test the math live. Switch between craft presets, customize components, slide the scrap multiplier, and observe how batch scale and labor wage create your true unit Cost of Goods Sold (COGS).
Bill of Materials (BOM) Costing Playground
Select a craft preset, adjust scrap rates, tweak component quantities, and see how material yields directly determine your true Cost of Goods Sold (COGS).
BOM Components6 items
| Component | Qty | Cost/Unit | Total | |
|---|---|---|---|---|
Golden Wax 464 Flakes (155g) Raw Material | $ | $1.48 | ||
Clean Scents Fragrance Oil (15g) Raw Material | $ | $1.15 | ||
ECO 10 Cotton Wick & Tab Assembly Hardware & Finding | $ | $0.18 | ||
8 oz Amber Glass Jar Packaging & Label | $ | $1.35 | ||
Black Metal Screw Lid Packaging & Label | $ | $0.42 | ||
Warning Label & Kraft Gift Box Packaging & Label | $ | $0.58 |
Production & Scrap Knobs
Adds $0.26 per unit to absorb unrecoverable workshop loss.
Total labor per unit: $1.17
Does Labor Belong in a Bill of Materials?
A common question from artisans is: “Where do I put my labor time in the BOM?”
In industrial accounting, a BOM tracks physical parts, while labor is tracked in a separate document called a Routing Sheet. In a small craft studio, separating them into separate binders is unnecessary overhead. However, you should still calculate them as distinct line items:
Keeping materials separate from labor ensures you never accidentally mark up labor twice or understate your true physical inventory value on tax day. To dig deeper into paying yourself living wages, read our guide on How to Price Handmade Products: Materials + Labor + Fees + Profit.
Free Bill of Materials Template Schema
If you are building your first BOM in a spreadsheet before moving to a dedicated tool, here is the standard 7-column schema every artisan business should maintain:
| Column | Field Name | Purpose & Example |
|---|---|---|
| A | Item Name | Exact supplier item name (e.g., “Golden Wax 464 Flakes”) |
| B | Category | Raw Material, Hardware, Sub-Assembly, or Packaging |
| C | Supplier & SKU | Where you reorder (e.g., CandleScience #GW464-45) |
| D | Bulk Package Cost | Invoice price including shipping ($84.00 for 45 lbs) |
| E | Usage per Unit | Exact quantity in finished unit (155g) |
| F | Unit Cost | Formula: =(D2/PackageUnits)*E2 ($0.64) |
| G | Scrap Rate | Estimated workshop loss factor (5% = 1.05 multiplier) |
While spreadsheets work for your first two products, they quickly break when suppliers increase prices. If Golden Wax increases by 12%, a static spreadsheet forces you to manually recalculate every single recipe row by row. In Batchable, updating your shared wax library price instantly recalculates every candle BOM in your entire catalog.
Maker BOM Questions Answered
Clear, straightforward answers to the questions artisans ask most when moving from kitchen recipes to formal manufacturing inventory.
How to make a Bill of Materials (BOM)?
To make a Bill of Materials (BOM), list every physical component required to produce one finished sellable unit across four categories: Raw Materials, Hardware/Findings, Sub-Assemblies, and Packaging. For each item, record its bulk purchase price, usage quantity per unit, calculated unit cost, and a Scrap Multiplier (typically 3% to 10%) to absorb workshop trimmings and spillage.
What is the difference between a recipe and a Bill of Materials (BOM)?
A recipe provides mixing steps and raw ingredients (e.g. 500g soy wax and 45g fragrance oil). A Bill of Materials (BOM) is an exhaustive manufacturing inventory list that adds physical containers, wicks, safety caution stickers, gift boxes, shipping tissue, and waste scrap factors to determine the true material cost of goods sold.
What is a single-level vs. multi-level BOM?
A single-level BOM lists all materials in a flat table for straightforward products. A multi-level BOM groups components into parent products and child sub-assemblies—such as preparing a 50-piece batch of pre-tabbed wick assemblies or an infused botanical oil base before using them in the final finished product.
How do you calculate scrap and waste in a BOM?
Scrap is calculated using a Scrap Multiplier: Adjusted Material Cost = Base Material Cost × (1 + Scrap Rate). For instance, if raw wax and fragrance cost $2.63 per candle and your pouring pitcher clings or spillage average 5%, multiply $2.63 by 1.05 to get an adjusted material cost of $2.76 per unit.
Should labor and overhead be included in a Bill of Materials?
In standard production accounting, a Bill of Materials strictly tracks physical parts and materials. However, to calculate your full Cost of Goods Sold (COGS), direct maker labor (Take-Home Hourly Wage × production hours) and allocated studio overhead are added immediately alongside the BOM total: COGS = Adjusted BOM Materials + Direct Labor + Studio Overhead.
How do I convert bulk supplier invoices into per-unit BOM costs?
Divide the invoice price by the total unit count in the package, then multiply by the exact quantity used in your batch yield: Unit Cost = (Bulk Invoice Price / Total Package Units) × (Usage Quantity / Batch Yield). For example, an $84 case of 45 lbs of Golden 464 soy wax equals $0.00411 per gram; an 8 oz candle using 155g of wax costs exactly $0.64 in raw wax.