How do I calculate a bill of materials for a handmade product?

How to calculate a bill of materials

A bill of materials is the full list of every input needed to make one unit of a product, with an exact quantity and unit for each line. Build it once per product and every other calculation, capacity, cost and reorder, falls out of it automatically.

The short version

List every inputInclude packaging, labels, wicks, jars, ribbon and boxes. Forgotten packaging is the most common reason a batch stalls.
Use one unit per materialPick grams, millilitres or pieces and stay consistent. Mixing kilos and grams is where most spreadsheets break.
Divide by batch sizeIf a batch of 24 uses 8 kg of flour, the BOM line is 333 g per unit. Always store the per-unit figure.
Add a waste factorSpillage, trimming and rejects are real. A two to five percent allowance keeps your plan honest.

Takeaway. Once the BOM is right, capacity, cost per unit and your shopping list stop being separate jobs.

Put it into practice

Makeable does this arithmetic for you every time your stock moves. You can try the capacity calculator on the home page without an account, or compare plans for makers, including the free tier when you are ready to keep your own numbers.