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.
A worked example: one chocolate cake
You bake a batch of 12 chocolate cakes using 48 eggs, 3.6 kg of flour, 1.44 kg of butter, 2.4 kg of sugar and 900 g of cocoa. Divide everything by 12 to get the per-unit BOM: 4 eggs, 300 g flour, 120 g butter, 200 g sugar and 75 g cocoa per cake.
Now add the packaging you actually use: one cake box, one cake board, one length of ribbon and one label per cake. Write them as lines with the unit piece. Your BOM now has nine lines, and every one of them can stall production if it hits zero. A perfect batter and no boxes is still a day you cannot ship.
Store each line in a single consistent unit. Flour in grams, never a mix of kilos and grams. Eggs in pieces, never a mix of pieces and trays. The unit you choose matters less than never mixing two.
The waste factor, honestly applied
Real kitchens and workshops lose material. Batter sticks to the bowl, wax spills, the first print of a label is crooked, one cake in twenty comes out wrong. If your BOM assumes zero waste, your capacity figure is optimistic and your cost per unit is understated.
Measure waste once per product: weigh what you started with, weigh what ended up in sellable units, and note the difference. For most food and craft products it lands between two and five percent. Apply it by multiplying each BOM line by your factor, so 300 g of flour at five percent waste becomes a planning figure of 315 g.
Resist the temptation to use a big safety number like fifteen percent to be safe. Inflated lines quietly shrink your apparent capacity and push you into ordering early and overstocking, which is its own cost.
Keep one BOM per product, and version it
Recipes change. You swap a supplier, adjust the sugar, move to a larger box. Each change is a new version of the BOM, and old accepted orders were costed against the old version. Keep the history rather than overwriting, so last month's margin numbers still make sense next quarter.
A common failure mode is three versions of the truth: the recipe card in the kitchen, the spreadsheet on the laptop, and the numbers in your head. Pick one system as the source and make the others copies. When the BOM changes, change it in the source first.
With one current BOM per product, every downstream number becomes a lookup: capacity is stock divided by BOM lines, cost per unit is BOM lines multiplied by prices, and the shopping list is the BOM multiplied by the orders you have accepted.
For information and estimates only. Makeable's formulas, batch limits and margin calculations are mathematical estimates based on your inputs. They are not certified accounting, financial, pricing or tax advice. You are solely responsible for setting your own wholesale and retail prices, ensuring profitability, and checking cost calculations before committing money.
Common questions
What is the difference between a recipe and a bill of materials?
A recipe describes how to make a batch, usually in batch quantities with method steps. A bill of materials is the same information normalised to one finished unit, including packaging, expressed in consistent units, and stripped of method. Production maths runs on the BOM, not the recipe card.
Should packaging really go in the BOM?
Yes. Boxes, jars, labels, wicks and ribbon are consumed every time you sell a unit, exactly like flour or wax. Leaving them out overstates your capacity and understates your cost per unit, and forgotten packaging is the most common reason a ready batch cannot ship.
How many decimal places should BOM quantities use?
Two is plenty for grams and millilitres. The error from rounding 333.33 g to 333 g is a fraction of a percent, far smaller than your waste factor. Precision beyond that is false confidence.
