Methodology · AACE 18R-97 · Q4 2025 Benchmarks
A transparent explanation of Class D cost methodology, estimate accuracy, benchmark sources, and the limits behind early construction cost ranges. Read this before treating any calculator output as a project budget.
Open the Calculator Browse ResourcesStep back first
A Class D estimate is a conceptual cost range for feasibility-stage decisions. It tests whether a project direction is financially realistic before drawings, quantity take-offs, and trade pricing are complete.
Purpose
Used to decide whether the project should proceed to deeper design and estimating.
Accuracy
The band is two-sided. The midpoint is a reference, not a promise.
Not
Not a quotation, tender price, financing basis, or contract value.
Example: a Class D estimate of C$20M at ±25% gives a realistic planning range of roughly C$15M to C$25M.
The band tightens when scope, building type, site conditions, servicing, regulatory triggers, and complexity are clearly described. When those inputs are uncertain, treat the number as a feasibility signal only.
Method
Each step adjusts the one before it. The range you see at the end reflects all four.
The estimate begins with a building-type cost range, usually per square foot or by comparable benchmark category, anchored to published data, historical projects, and regional market conditions.
Benchmark sources
Project-specific inputs move the cost above or below the base range. The more of these are known, the more useful the estimate becomes.
Project-specific signals
A feasibility budget should carry design fees, permits, development charges, construction management, escalation, contingency, and HST exposure where applicable.
Some scopes need further review before the range can be relied on. These triggers can change budget, timeline, design scope, and approval path.
Limits
A Class D range is a planning tool. Before it becomes a commitment, three things have to happen.
It does not represent an offer to construct the project at a stated price.
Tender pricing and contract values need clearer drawings, specifications, scope boundaries, and trade pricing.
Structural, mechanical, electrical, fire protection, PSHSR, equipment, or certification issues may need professional review first.
Structural modifications, MEP capacity, PSHSR triggers, equipment platforms, fire protection, occupancy changes, and code compliance can materially affect the budget. ProWise Engineering can review technical scope before the estimate is used as a planning baseline.
FAQ
Class D is a conceptual estimate used for feasibility-stage planning. It helps owners understand an early cost range before full drawings, trade pricing, and detailed quantity take-offs are available.
No. A Class D estimate is not a financing basis or contract value. Lenders and formal approvals usually require a tighter estimate class supported by drawings, scope definition, and professional review.
Request a detailed estimate when drawings, site information, project scope, and regulatory requirements are developed enough to support a Class C, Class B, or tender-stage budget.
Next Step
Run the calculator to understand the early cost range, then speak with ProWise Construction when the project needs scope review, delivery planning, or a more detailed estimate.
Open the Calculator Request a Scope ReviewClass D conceptual estimate information only. Not a quotation. Not a basis for financing or contract value. Material decisions require qualified engineering, quantity surveying, and construction review.
