Cost Business Case

Model volumes, margin and investment: the target cost must still make money at the volumes you really expect.

Time1 h
FormatSolo
StageTarget

Cost Business Case: what it is and why it works

A cost business case tests whether a target cost still makes money once you account for everything the project must spend to reach it and for the volumes you realistically expect. You list the one-time costs the project will bear, such as development, tooling, certification, ramp-up and working capital, and the benefits it produces, such as margin gain per unit, volume effects and avoided costs. From these you compute payback and break-even volume at the target price, then repeat the calculation at the pessimistic cost. The result fits on one page for the steering committee.

Many cost reduction and new product projects look attractive only because they are evaluated at best-case volumes and optimistic costs. Running the case at the pessimistic end of the cost window, with volumes sales will actually commit to, separates projects that are robust from those that depend on everything going right. It forces the investment side into the conversation early: a redesign that saves $3 per unit but needs $2 million in tooling is a different decision from one that needs $200,000. The case links the target cost definition to stage-gate decisions, and lifecycle cost analysis extends it when operating and service costs matter to the customer.

What you need

The target cost and the current or baseline cost per unit
One-time project costs: development, tooling, certification, ramp-up, working capital
Realistic and pessimistic volume forecasts, preferably ones sales will commit to
The cost window, including the pessimistic cost level
The company's hurdle criteria, such as maximum payback or minimum net present value

What you get

Payback period and break-even volume at the target cost
The same figures at the pessimistic cost and realistic volume
A one-page summary for the steering committee with a clear go, rework or stop recommendation
A list of the assumptions that most affect the result

When to use it

When the target is set on best-case volumes nobody believes.

How to do it, step by step

List all costs the project will bear: development, tooling, certification, ramp-up, working capital.
List the benefits: margin gain, volume effect, cost avoidance.
Compute payback and break-even volume at the target price.
Run the pessimistic scenario: does the case still close at the pessimistic cost?
Write the two numbers on one page for the steering committee.

Worked example: Next-generation blower package for wastewater aeration

Illustrative scenario — figures are realistic but not from a real company.

A manufacturer of blower packages for wastewater aeration planned a redesign to cut unit cost from $21,400 to a target of $18,900. Sales initially projected 400 units a year, but last year's shipments were 240. Company rules required payback within three years.

The project listed one-time costs: development $620,000, tooling $380,000, certification and testing $90,000, ramp-up losses $110,000 and extra working capital $150,000, for a total of $1.35 million.
Benefits were the unit saving: $2,500 at the target cost, but only $1,500 if the redesign landed at the pessimistic cost of $19,900.
At a realistic 260 units a year, payback was about 2.1 years at the target cost but 3.5 years at the pessimistic cost. Cumulative break-even volume was 540 units at target and 900 units at the pessimistic cost.
The pessimistic case failed the three-year rule, so the team looked at the investment side and found that soft tooling for the first year of production would cut tooling spend by $250,000.
The one-page summary showed both scenarios, the revised investment and the three assumptions that drove the result: volume, pessimistic cost and tooling approach.

Result. With investment at $1.1 million, pessimistic payback came down to about 2.8 years and the project was approved. The committee asked for a volume check after six months before releasing hard tooling. The team learned that the investment side of the case was as negotiable as the unit cost.

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Common pitfalls and how to avoid them

Using sales' best-case volume as the base case.Build the base case on volumes sales will commit to, and show the upside separately.
Leaving out ramp-up losses, working capital or certification costs.Use a standard checklist of one-time costs for every business case.
Showing only the target-cost scenario.Always show the case at the pessimistic cost; if it only closes at the optimistic cost, say so clearly.
Relying on simple payback for long-lived investments.Add net present value or discounted payback when the investment spans several years or the discount rate is significant.

Frequently asked questions

How do you calculate break-even volume for a cost reduction project?

Divide the total one-time investment by the saving or contribution gained per unit. If a redesign costs $1 million and saves $2,000 per unit, you need 500 units to break even. Run the calculation at both the target and the pessimistic cost, and compare the result with the volumes you realistically expect over the product's life.

What is the difference between payback and NPV in a business case?

Payback measures how long it takes for cumulative benefits to recover the investment, ignoring the time value of money and anything after the payback point. Net present value discounts all future cash flows to today and subtracts the investment. Payback is easy to communicate; NPV is better for comparing projects of different sizes and lifetimes. Many committees look at both.

What costs should a product cost business case include?

Include all one-time costs the project triggers: engineering and development hours, tooling and fixtures, testing and certification, supplier qualification, ramp-up scrap and inefficiency, and additional working capital such as inventory. On the benefit side, count unit cost savings, volume effects and avoided costs, and state each assumption so reviewers can challenge it.

Origin

Business case practice — engineering economics and stage-gate methodology (Cooper, 1990).

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