What goes into a should-cost
A supplier’s quote is a single number. A should-cost model breaks it into seven parts, each worked out from
engineering facts and market rates, and each one something you can discuss separately with the supplier.
Raw material: 32%Weight × market price ÷ yield. Check it against commodity price indices and link it to an index in the contract.
Process & machine: 24%Cycle time × machine-hour rate. Question the cycle times using engineering calculations, and compare rates with others in the same region.
Direct labour: 12%Operators per machine × local wage. How much is automated is the part you can negotiate.
Scrap & yield: 4%Assumptions about how many parts come out right first time can hide money, so ask for the real OEE figures.
Overhead: 14%This depends on how busy the plant is. A supplier running at 60% capacity is charging you for machines standing idle.
SG&A: 8%Sales, admin and engineering costs. Compare them across your suppliers and negotiate down any that stand out.
Margin: 6%A fair profit the supplier can live on. Being open works better than squeezing, and anything above it can be shared through a gain-share deal.