Cost Estimate

A company considering fitting out a new laboratory may have only early sketches that support a broad estimate, while detailed engineering may change the equipment list, building works and approvals, so the figure must be read with its scope and maturity. AACE explains that estimate class primarily follows maturity of scope definition, while accuracy is affected by uncertainty, and the US Government Accountability Office's cost-estimating guide describes reliable estimates as necessary for realistic planning and management.

These are methods, not guarantees of a particular final price. Define the decision and set the scope, because an early options comparison needs different detail from a funding approval or supplier negotiation, and a number without stated deliverables and exclusions cannot be compared with a later price.

Break work into a logical structure of tasks, materials, labour, equipment and specialist services to catch omissions, and measure quantities from source drawings or assumptions, noting if they are preliminary. Choose unit rates from supplier quotations, past projects or market data, adjusting for location, date and specification.

Account for indirect costs such as supervision, design, permits, logistics and project administration, which may sit outside direct construction work, and state the treatment of taxes and duties, since a quoted base price may exclude recoverable or non-recoverable tax, import costs and fees. Add schedule effects, because a delayed project can face escalation, extra rent or longer site overhead, and treat currency risk by showing the exchange rate and sensitivity for imported equipment rather than hiding it in a single number.

Separate contingency, which is an allowance for identifiable uncertainty within the defined scope using a documented risk method, and remember that a flat percentage is an assumption, not a universal rule. Do not use contingency to hide missing scope, since a known building permit or essential machine is a base cost, and identify owner reserves separately, because major scope changes or exceptional risks may require a management reserve that should not be silently added to a contractor's estimate.

Record estimate class or maturity and avoid false precision: quoting $1,045,327 from rough area rates can imply certainty that the inputs do not support, so round appropriately and show a range. Test alternatives, since different layouts, materials or delivery methods can change both cost and operating benefit, so compare equivalent scopes, and review supplier quotes for validity dates, exclusions, delivery terms and installation responsibilities because a low quote may omit major work.

Use historical data carefully by adjusting past costs for size, complexity, location and inflation, since a prior project's total is not a plug-in answer. Get independent review from another estimator who can check quantities, rates and missing interfaces, especially before a major commitment.

Link the estimate to the schedule, since accelerated delivery may require overtime or premium freight, and when the design changes distinguish scope growth from rate changes and estimating corrections. After work begins, track actual costs against commitments and update a forecast to complete rather than calling every variance an overrun, and distinguish cost from price because a supplier price includes margin and commercial risk.

State confidence with a range and risk register, obtain approval separately because an estimate informs a decision but does not grant permission to spend, and remember that for an owner a useful estimate explains what is included, how it was calculated and how much could change.