Manufacturing
What is a bill of materials (BOM)? Meaning and example
Definition
Bill of materials: A bill of materials (BOM) lists the raw materials, packing and quantities needed to make a set amount of a finished product, like a recipe for production.
Also called: BOM, BOM in manufacturing, recipe, formula, material list
What a BOM contains
A bill of materials is the recipe a factory or kitchen works from. Food and cosmetics makers often call it a formula or recipe; engineering firms call it a BOM. It should say exactly what goes into one batch, so anyone on the floor makes the product the same way and the business knows what to buy.
- The finished product and the batch size the BOM makes, such as 10 kg or 500 bottles
- Every material, with its quantity and unit
- Packing materials: pouches, jars, labels and cartons
- The expected process loss, if any
- Short instructions, such as the order of mixing and roasting times
How to scale a BOM
To plan a run, scale each material by the ratio of the planned output to the BOM's batch size: material needed = BOM quantity × planned output ÷ BOM batch size. Then compare with stock: shortfall = material needed − stock available − quantity already on order. Anything short is what you must buy before the run can start. Round up materials bought in fixed packs, since you cannot buy 0.7 kg of a spice sold only in 1 kg bags.
Common BOM mistakes
Forgetting packing materials is the classic one: the masala is ready but the pouches are not. Others are writing the BOM in a different unit from your stock, such as grams in the BOM and kg in stock, without converting; not updating the BOM when the recipe changes; and ignoring process loss, such as moisture lost in roasting, so every batch comes out short of plan. Some products also have levels: a spice blend made first, then packed into pouches as a second step, each with its own BOM.
Worked example
A nine-spice garam masala BOM
A masala maker's BOM makes 10 kg of garam masala from coriander 3.5 kg, cumin 2 kg, black pepper 1.2 kg, cinnamon 0.9 kg, cardamom 0.8 kg, cloves 0.6 kg, dry ginger 0.5 kg, bay leaf 0.3 kg and nutmeg 0.2 kg. To make 50 kg, every quantity is multiplied by 50 ÷ 10 = 5, so cloves become 3 kg. The godown has 1.8 kg of cloves and 0.5 kg on order, so the shortfall is 3 − 1.8 − 0.5 = 0.7 kg, and 0.7 kg of cloves goes on a purchase order before the run.
In managemate
managemate calls a bill of materials a formula. A formula names the finished product and the quantity it makes, lists up to 100 ingredients in the usage packs you choose, and holds written instructions for the team. When you plan a production run, managemate scales every ingredient to the quantity you want and shows, at the production location, what is needed, what is in stock, what is on order and the shortfall. Missing materials become draft purchase orders in one step, and a run cannot start while materials are short. An ingredient can be another product you make, but each level is its own run. There is no field for expected loss: record the materials actually used and the quantity made when you complete the run.
Where this shows up in managemate
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