Order-of-magnitude estimating provides an early planning range from basic project parameters and stated assumptions, helping an owner test feasibility before committing to detailed design.
Feasibility-Stage Numbers, Fast
When a project is still an idea, a building type and approximate size can support initial cost screening. Location, site assumptions and quality expectations are documented alongside the planning range.
Use a ROM estimate for screening, not commitment
An order-of-magnitude construction estimate helps decide whether an idea merits further study. It may rely on building area, capacity or another high-level parameter, supported by clearly stated assumptions. Its value is the decision boundary it establishes: a plausible planning range and the unknowns that could move the project outside that range.
- State the project type, size metric and intended comparison.
- Identify major inclusions such as site work and utility connections.
- Separate land, financing, design and other owner costs when excluded.
- Explain uncertainty using project-specific risks rather than a universal percentage.
Know when to retire the rough estimate
A ROM should be replaced when the project changes use, location, capacity or design concept, or when better documents become available. Comparing a later contractor bid to the original rough number without reconciling scope can be misleading. Use the early estimate to approve further investigation, test an acquisition assumption or select a concept; request a more developed estimate before procurement or construction-price commitments.
Order-of-Magnitude Estimating FAQs
- How fast can you turn around an order-of-magnitude number?
- Send the program, location and required decision date. We confirm the available information, scope and delivery commitment in the proposal before starting.
- How wide is the accuracy range on this type of estimate?
- The range depends on project definition, industry and risk. We identify the major unknowns and the basis of the range instead of applying one percentage to every early-stage project.
- How much does order-of-magnitude estimating cost in Texas?
- The estimating fee depends on the available design information, number of concept options, area or capacity metrics and the estimate class required. Project construction value by itself is not a dependable measure of estimating effort. Send the current files, project location and required date for a fixed-fee proposal; it will identify the exact scope and delivery commitment before work begins. The proposal is limited to order-of-magnitude estimating, while the conceptual estimating overview can be used when a broader package is required.
- What should I send for order-of-magnitude estimating?
- Provide the program, site plan, narratives, sketches, system assumptions and target design milestone, even when a coordinated drawing set does not yet exist. For this focused service, the review pays particular attention to use a rom estimate for screening, not commitment. Include the Texas project city or county, current document date, addenda and the decision the output must support. Incomplete information can still be reviewed, but every required allowance or unresolved scope boundary is recorded instead of being presented as measured fact.
- How is order-of-magnitude estimating checked for a Texas project?
- The estimator checks the document issue, measurement trail, scope interfaces and requested output before delivery. The Texas location, design maturity, pricing date and unresolved scope are stated with the estimate class. Market escalation and contingency remain separate so an early planning range is not presented as bid-level certainty. The completed file keeps quantities, pricing assumptions, exclusions and open questions visible so the contractor or owner can review the basis before using the number. Source: AACE estimate-class guidance