BOM Cost Calculator
Bill-of-materials costing for furniture: waste-inflated buy quantities, line and total costs, cost per product and a selling price from your target margin.
A product costs what its parts cost - plus the material you buy and never use. Each BOM line here carries a waste allowance on top of the net quantity, because dried S4S lumber realistically yields 80-85%, rough lumber 70-75%, and nested panels 88-95%. The calculator rolls every line into a material cost, divides it across the batch, adds labour per product, and applies your margin the honest way: price = cost / (1 − margin), so a 30% margin on $63.34 quotes at $90.49, not $82.34.
FAQ
How much waste should I add to lumber?
Plan 15-20% on dried S4S lumber, 25-30% on rough-sawn stock (defects and grain can push it to 40-50%), 5-12% on panels cut with nesting software and around 15% for manual panel cutting.
How do I price a product from cost and margin?
Price = cost / (1 − margin). Margin is taken on the selling price, so 30% margin on a $63.34 product quotes at $90.49. Adding 30% to cost ($82.34) is a markup, not a margin, and quietly underprices the work.
What goes into cost per product here?
Material lines inflated by their waste allowances, divided by the number of products in the batch, plus optional direct labour per product. Overhead, finishing consumables and freight need their own lines or their own costing.
Why buy quantity and not net quantity?
You purchase material, not yield: the 0.030 m³ of acacia in the legs means buying 0.0375 m³ at 25% waste. The buy-quantity column is what you order; the net quantity is what survives in the product.