Make-or-buy decision
A make-or-buy decision determines whether a company should produce a part, process, or service in-house or purchase it from an outside supplier. Done well, it weighs total cost of ownership, internal capability and capacity, intellectual property exposure, and supply risk rather than comparing internal unit cost to a supplier's quoted price.
Examples
Machined bracket: Internal costing shows $11.40 for a 6061 bracket against an $8.90 quote. Strip out $2.80 of fixed overhead allocation that survives outsourcing either way and the true internal marginal cost is $8.60. At 40,000 units a year, buying would have added $12,000 in annual cost while idling a paid-for CNC cell.
Capacity-driven buy: A motor housing costs $14.20 to make in-house versus a $15.10 quote, but the same cell is the bottleneck for a higher-margin line. The team buys the housing and refills the freed 1,100 machine hours with work contributing $190 per hour.
IP-driven make: A robotics company gets gearbox bids 18% below internal cost, but the drawing package would hand a supplier its core differentiation. It keeps the gearbox in-house and outsources the commodity shafts instead.
Definition
Most make-or-buy analyses that go wrong fail the same way: someone compares the supplier's piece price to an internal cost estimate and stops. The internal number arrives loaded with allocated overhead that will not disappear if the work leaves; the quote arrives stripped of tooling transfer, qualification builds, freight, and the cost of managing a supplier far away. The only fair comparison is total cost of ownership on both sides.
Cost is also just one of four dimensions. Capability: can your equipment hold the tolerance, and can the supplier prove it can? Capacity: what does the machine not produce while it produces this part? Control: does the part carry intellectual property you want kept inside, and can you live with an outside lead time?
A value chain lens keeps the logic honest: make what differentiates the product, buy what does not. The same machining work can be 'make' for a company whose margin lives in that part and 'buy' for one whose margin lives in software.
Decisions are reversible on paper and sticky in practice. Once tooling and process knowledge move to a contract manufacturer, re-insourcing takes years, so test the quote itself with a should-cost analysis before treating it as truth. Direct-materials teams use platforms like LightSource to compare supplier quotes line by line against should-cost baselines before committing the buy side of the decision.
Frequently asked questions
What is a make-or-buy decision?
A make-or-buy decision determines whether a company should produce a part, process, or service in-house or purchase it from an outside supplier. Done well, the analysis weighs total cost of ownership, internal capability and capacity, intellectual property exposure, and supply risk rather than comparing internal unit cost to a supplier's quoted price.
Why do make-or-buy analyses go wrong?
Most make-or-buy analyses that go wrong compare the supplier's piece price to an internal cost estimate and stop. The internal number arrives loaded with allocated overhead that will not disappear if the work leaves, while the quote arrives stripped of tooling transfer, qualification builds, freight, and the cost of managing a distant supplier. In one example, stripping $2.80 of surviving overhead allocation from an $11.40 internal cost revealed a true marginal cost of $8.60 against an $8.90 quote, reversing the answer.
What factors matter beyond cost in a make-or-buy decision?
Cost is one of four dimensions in a make-or-buy decision. Capability asks whether your equipment can hold the tolerance and whether the supplier can prove it can; capacity asks what the machine does not produce while it produces this part; control asks whether the part carries intellectual property you want kept inside and whether an outside lead time is livable. A value chain lens keeps the logic honest: make what differentiates the product and buy what does not.
Can you reverse a make-or-buy decision?
Make-or-buy decisions are reversible on paper and sticky in practice. Once tooling and process knowledge move to a contract manufacturer, re-insourcing takes years, so the quote deserves testing with a should-cost analysis before being treated as truth. The same machining work can be 'make' for a company whose margin lives in that part and 'buy' for one whose margin lives in software.
When does buying make sense even at a higher price?
Buying can win even at a higher piece price when internal capacity has better uses. In one case a motor housing cost $14.20 to make against a $15.10 quote, but the same cell was the bottleneck for a higher-margin line, so the team bought the housing and refilled the freed 1,100 machine hours with work contributing $190 per hour. The reverse also holds: a robotics company kept a gearbox in-house despite bids 18% below internal cost because the drawings would hand a supplier its core differentiation.