Cost-Benefit Analysis
A cost-benefit analysis weighs the total expected costs of a project against its total expected benefits — usually in monetary terms — to judge whether it is worth doing and to compare it against alternatives.
A cost-benefit analysis (CBA) is a systematic technique for evaluating the financial merit of a decision by summing its expected costs and benefits, converting them to comparable (usually monetary) terms, and comparing them. It typically accounts for the time value of money by discounting future amounts to present value, and produces measures such as the benefit-cost ratio, net benefit, or NPV. CBA is the analytical core of a business case and a common input to project selection and prioritisation.
Cost-Benefit Analysis at a glance
- Category
- Planning & Initiation · Cost, Budget & Earned Value · Leadership, Strategy & Decisions
- Type
- Tool / technique
- Appears in
- 3 sections
- Related
- Economic Feasibility, Return on Investment, Legal Feasibility
Why it matters
Resources are finite, and CBA provides an objective, comparable basis for deciding where to spend them. By forcing costs and benefits to be quantified and put on the same footing, it exposes options that sound attractive but do not pay off, and highlights those with the best return. It also creates a documented rationale that can be revisited — and it disciplines optimism by making assumptions explicit.
When to use it
Use CBA when evaluating whether to undertake a project, choosing between options, or justifying an investment — during selection, initiation and at stage gates. It is most reliable when costs and benefits can be reasonably quantified; for decisions dominated by hard-to-monetise factors (strategic fit, safety, morale), it should be supplemented with qualitative analysis rather than used alone.
How to use it
- Define the scope and the options being compared (including doing nothing).
- Identify and quantify all costs — one-off and ongoing, direct and indirect.
- Identify and quantify all benefits, including, carefully, intangible ones.
- Discount future costs and benefits to present value using an appropriate rate.
- Compare: compute net benefit / benefit-cost ratio / NPV and recommend accordingly.
Example
A CBA for automating invoicing: costs are €120k (software + implementation) plus €10k/year support; benefits are €60k/year in saved labour and €15k/year in fewer errors. Over five years, discounted at 10%, the benefits’ present value exceeds the costs, giving a positive NPV and a benefit-cost ratio above 1 — so the project is financially justified.
Template
A CBA template lists costs and benefits over time, applies a discount rate, and computes present values, net benefit and the benefit-cost ratio.
Tools
Formula
FAQs
How does cost-benefit analysis handle the time value of money?
How do you value intangible benefits?
What is the difference between CBA and a business case?
Alternatives
- NPV / IRR analysis — the discounted-cash-flow core of CBA
- Cost-effectiveness analysis — compares cost per unit of outcome when benefits are not monetised
- Multi-criteria decision analysis — for weighing non-financial factors