Capex definition
Capital expenditure (capex) refers to funds used by an organisation to acquire, maintain, or upgrade physical or intangible long-term assets — equipment, property, vehicles, technology systems, or intellectual property. Unlike operating expenditure (opex), which is expensed in the period it is incurred, capex is capitalised on the balance sheet and depreciated (or amortised) over the useful life of the asset.
The distinction between capex and opex is one of the most consequential judgements in corporate finance: it affects reported profit (capex does not hit the P&L immediately; opex does), tax treatment (the timing of deductibility differs), and cash flow presentation. In practice, the boundary between the two is often contested — particularly for technology investments, where the question of whether a system upgrade is a "maintenance" (opex) or "improvement" (capex) can have significant P&L implications.
Capex vs Opex — the key difference
Opex (operating expenditure) covers the day-to-day costs of running the business: salaries, rent, utilities, marketing, professional services. These costs are expensed fully in the period they are incurred — they appear on the P&L immediately and reduce profit in the same period.
Capex covers investments in long-term assets. A piece of manufacturing equipment purchased for £500k is not expensed immediately; it is capitalised (appears as an asset on the balance sheet) and depreciated over its useful life — say, ten years, at £50k per year. Only the annual depreciation charge hits the P&L, not the full purchase price.
This treatment has a significant impact on reported profit. A business that shifts investment from opex to capex will report higher short-term profits (because the cost is deferred through depreciation) but lower cash flow (because the full cash outflow happens immediately at purchase). FP&A teams must track both the P&L impact and the cash flow impact of capex decisions.
How to build a capex forecast
A capex forecast typically has three components: maintenance capex (spending required to maintain existing assets at current performance levels), growth capex (investment in new capacity or capability), and project capex (one-off investments in specific initiatives — a new system, a new facility, an acquisition).
Each category requires a different forecasting approach. Maintenance capex is relatively predictable and can often be modelled as a percentage of the existing asset base. Growth capex requires a pipeline view — what investments are planned, at what cost, and on what timeline. Project capex requires project-level tracking: budget vs actual vs forecast to complete, with milestone-based cash flow timing.
For further reading on capex forecasting best practices, see our detailed guide: Best Practices for Capital Expenditure Forecasting.
Capex in board reporting and investment committees
Capital expenditure decisions are among the most consequential a business makes — committing cash today for benefits that may not materialise for years. Board-level capex reporting should address three questions: Are we spending the capex we planned to spend, and if not, why not? Are the projects we have committed to delivering against their business case? And what new capex commitments are being proposed and on what terms?
For significant capex commitments, many boards require a formal investment appraisal — a discounted cash flow (DCF) analysis or return on investment (ROI) calculation that tests whether the expected returns justify the capital outlay and the risk. FP&A is typically responsible for building and stress-testing these investment cases.
Common capex forecasting mistakes
Optimism bias: capex projects almost universally cost more and take longer than initially planned. Finance teams that do not build contingency into capex forecasts will regularly report cost overruns.
Ignoring cash flow timing: capex is recognised in the cash flow statement when cash is paid, not when assets are delivered. Project delays mean cash outflows shift forward — but the cash needs to be available when the payment is due, not when the asset arrives.
Conflating budget and forecast: the capex budget is what was approved; the capex forecast is what will actually be spent. Finance teams that report budget vs actuals without maintaining a current capex forecast lose visibility of cash commitments in real time.
Incomplete opex consequences: every capex decision has opex consequences — new equipment needs maintenance contracts and operator training; new technology needs licences and support. Capex forecasts that ignore these downstream opex impacts produce incomplete business cases and budget surprises.
