Construction business guide
How to estimate construction jobs
For construction work, a reliable process should measure scope, quantities, uncertainty and approval before work starts. Record scope, drawing revision, progress, change order and approval, and itemize each work phase, labor hour, material and equipment day that affects the price.
Build a construction estimate by work package, with quantities, labor, materials, equipment, subcontract quotes, allowances and overhead shown on a consistent basis. State exclusions and the change process, then keep cumulative progress billing separate from the estimated contract value.
Organize the estimate by measurable work
Split the scope into work packages such as preparation, structure, installation and finishing. Each package should identify quantities, specifications and the source of its labor or supplier cost. A single total is difficult to revise when one part of a project changes.
Record the drawing or specification version used. Distinguish known prices from provisional allowances and explain what an allowance covers. Do not include the same equipment, supervision or delivery charge in both a trade package and project overhead.
Worked package cost summary
This example illustrates a price calculation and is not a construction market benchmark. Its target margin uses total allocated project cost, so it should not be confused with financial-statement gross margin based only on cost of sales.
| Category | Example |
|---|---|
| Labor | $8,000 |
| Materials | $12,000 |
| Equipment | $2,000 |
| Subcontract work | $4,000 |
| Allocated overhead | $3,000 |
| Total allocated project cost | $29,000 |
| Price at a 20% margin on this cost basis | $29,000 ÷ 0.80 = $36,250 |
Keep changes and payment stages traceable
State the validity period, schedule assumptions, excluded work, payment stages and method for approving a change. Identify any contingency separately and explain who may authorize its use. A contingency should not conceal a known omitted scope.
An accepted estimate sets the starting record. Track approved changes to obtain the current contract value, then deduct prior billings when preparing each progress invoice. Where retainage applies, show it separately under the agreement. An estimate, payment application and payment receipt should remain distinguishable.
Frequently asked questions
What should a construction allowance show?
Identify the work or purchase covered, the assumed amount or quantity and the method for replacing the allowance with the approved actual scope and price.
How does an estimate relate to progress billing?
The accepted estimate and approved changes establish the contract value. Each progress billing calculates the current amount from earned work, prior billings and contractual adjustments.