Executive summary
Cost the design package to a defined estimate class, apply contingency proportionate to design maturity and remaining risk, and phase the result into a cash-flow schedule aligned to the project timeline. This approved budget is the figure financing strategy must raise and procurement planning must not exceed without formal change control.
This stage receives a buildable design from engineering preparation; costing accuracy is bounded by how mature that design is, so the estimate class should be stated alongside the number.
The approved budget becomes the baseline against which every later cost variance is measured through to commissioning.
What this stage must resolve
- A completed design package awaiting investment-grade costing
- Need to present a single approved capital figure to the board or lenders
- Contingency levels not yet reconciled with remaining design and market risk
- Cash-flow phasing required to align with financing drawdowns
- Escalation risk on long-lead items or volatile input costs
Work performed in this stage
Class-appropriate estimating
Cost estimate accuracy matched explicitly to design maturity (e.g. budgetary vs. definitive).
Contingency allocation
Risk-based contingency by scope area rather than a flat percentage.
Escalation provisioning
Allowance for input cost and currency movement over the build period.
Cash-flow phasing
Aligns spend timing with construction milestones and financing drawdown schedules.
Owner's cost inclusion
Captures internal project team, insurance and commissioning costs often omitted from contractor quotes.
Comparison table
| Design maturity | Typical estimate class | Expected accuracy range |
|---|---|---|
| Concept / requirements only | Order-of-magnitude | ±30-50% |
| Basic engineering | Budgetary | ±15-30% |
| Detailed engineering | Definitive | ±5-15% |
| Firm supplier quotations | Control estimate | ±3-10% |
Estimate class and expected accuracy
Risks and governance considerations
- Owner's costs and commissioning costs are the most commonly underestimated line items
- Contingency should decline as design maturity increases, not be fixed at a single percentage throughout
- Currency exposure on imported equipment should be explicit, not absorbed into a general contingency
- The approved budget, once set, should be changed only through formal change control, not informally revised
What to prepare
- Completed engineering design package
- Line-item cost estimate with stated accuracy class
- Risk-based contingency by scope area
- Phased cash-flow schedule
- Owner's costs and commissioning cost allowance
What to measure
Frequently asked questions
What contingency level is typical?
It varies by design maturity and project complexity; the key discipline is stating the basis, not quoting a single universal figure.
Should the budget be fixed before financing is arranged?
The budget should be approved internally first; financing strategy then structures funding against that approved figure.
What is the biggest source of budget overrun?
Scope changes introduced after the budget is approved without formal change control, followed by underestimated owner's costs.
Related investment and financing knowledge
Project Lifecycle Stage
Engineering Preparation
Project Lifecycle Stage
Financing Strategy
Project Financing Knowledge
CAPEX or OPEX: Choosing How to Fund Capacity
Project Financing Knowledge
Financial Planning for Multi-Year Capital Programmes
CAPEX Intelligence
Industrial CAPEX Planning
Project Financing Knowledge
Working Capital Planning Around Capital Projects
Continue on the platform
Educational, supplier-neutral and financing-neutral
Global B2B Group does not sell equipment and does not represent lenders, export credit agencies or development banks. This material is published to help industrial organisations plan, structure and prepare capital projects. It is general information for decision-making, not financial, legal or tax advice.