Construction estimating is the process of forecasting what a project will cost to build before the work starts. An estimate converts drawings and specifications into quantities, quantities into labor, material, and equipment costs, and those direct costs into a price that includes the contractor’s time-based costs, overhead, and profit.
Owners use estimates to set budgets. General contractors use them to bid and to buy out subcontracts. Subcontractors use them to price their trade scope. The method is broadly the same in each case; what changes is the level of detail and how much design information is available.
What an Estimate Contains
A complete construction estimate generally has five layers:
| Layer | What it covers | Examples |
|---|---|---|
| Direct material | Everything that gets installed | Concrete, rebar, studs, drywall, conduit, wire, pipe, ductwork |
| Direct labor | Hours to install, times a burdened wage rate | Carpenters, ironworkers, electricians, plumbers |
| Equipment | Owned or rented equipment tied to the work | Lifts, excavators, pumps, cranes |
| General conditions | Time-based project costs | Supervision, trailer, temporary utilities, cleanup, safety |
| Overhead and profit | Company costs and fee | Home-office overhead, profit, sometimes bonds and insurance |
On a GC estimate, much of the direct cost arrives as subcontractor bids rather than self-performed labor and material.
Types of Estimates
Estimates get more detailed as the design develops. AACE International’s Recommended Practice 18R-97 describes five estimate classes, from Class 5 (least project definition, widest accuracy range) to Class 1 (most defined, narrowest range). In everyday commercial work, estimators use terms like these:
| Stage | Common name | Typical basis |
|---|---|---|
| Feasibility | Order of magnitude | Cost per SF or per unit from historical data |
| Schematic design | Conceptual budget | Systems and assemblies, SF models |
| Design development | Detailed budget | Partial quantities, assemblies, allowances |
| Construction documents | Bid estimate | Full quantity takeoff and priced line items |
| Construction | Change order estimate | Quantities and pricing for the specific change |
See our conceptual estimating guide for early-stage budgets.
The Estimating Workflow
1. Plan review and scope definition
Read the whole set: architectural, structural, civil, MEP, fire protection, and the project manual. Log addenda, identify the bid form requirements, and write down the scope boundaries for your trade or contract. Unclear or conflicting items become RFIs, not assumptions buried in a number.
2. Quantity takeoff
Measure every item from the drawings, organized by CSI MasterFormat division (for example 03 Concrete, 05 Metals, 09 Finishes, 26 Electrical). Digital tools such as Bluebeam Revu and PlanSwift speed this up, but the rules are the same as manual takeoff: measure net quantities, separate items that price differently, and apply waste factors deliberately. Our material takeoff guide goes deeper.
3. Pricing
Multiply quantities by unit costs. Material pricing should come from supplier quotes where possible. Labor pricing comes from productivity (labor-hours per unit) times a burdened wage rate that includes payroll taxes, workers’ compensation, and fringes; see our labor burden guide. Cost databases such as RSMeans are useful as a check and for filling gaps.
4. General conditions, overhead, and profit
General conditions are driven mainly by schedule duration. Overhead and profit are applied as markups, and the order and basis of those markups should be consistent across your estimates.
5. Review and bid
Check the estimate against the scope list, compare unit costs with history, level subcontractor bids, and write the qualifications. Then submit on the required bid form.
Worked Example 1: Slab-on-Grade Concrete Quantity
Example: a 120 ft x 80 ft slab-on-grade, 6 in thick.
- Area: 120 ft x 80 ft = 9,600 SF
- Thickness: 6 in = 0.5 ft
- Volume: 9,600 SF x 0.5 ft = 4,800 CF
- Cubic yards: 4,800 CF / 27 = 177.78 CY
- Waste allowance (assumed 5%; typical allowances vary with subgrade and placement method): 177.78 x 1.05 = 186.67 CY
- Order quantity, rounded up: 187 CY
Thickened edges, turndowns, and depressions would be calculated separately and added.
Worked Example 2: From Direct Cost to Bid Price
Example (illustrative figures): a project with $1,200,000 in direct costs (subcontracts, self-performed labor, material, and equipment) and an 8-month schedule.
- General conditions: 8 months x $12,000 per month = $96,000
- Subtotal: $1,200,000 + $96,000 = $1,296,000
- Overhead at 6%: $1,296,000 x 0.06 = $77,760
- Subtotal: $1,296,000 + $77,760 = $1,373,760
- Profit at 5%: $1,373,760 x 0.05 = $68,688
- Bid price before bonds and any taxes: $1,373,760 + $68,688 = $1,442,448
Note the difference between markup and margin. A 5% markup on cost produces a profit margin of $68,688 / $1,442,448 = 4.76% of the selling price. Mixing the two up is a common way to leave money on the table. Overhead and profit percentages vary widely by company, market, and project size; these are only for illustration.
Estimating Checklist
- All drawing disciplines and the project manual reviewed; addenda logged
- Scope boundaries written down for each trade or bid package
- Quantities organized by CSI MasterFormat division
- Waste factors stated by material, not buried in unit prices
- Labor priced from labor-hours and a burdened wage rate
- Major material pricing from current supplier quotes, dated
- General conditions tied to the actual schedule duration
- Subcontractor bids leveled for scope before comparing price
- Inclusions, exclusions, and assumptions written into the bid
- A second person reviews the estimate before it goes out
Common Mistakes
- Skipping sheets. Missing the civil, fire protection, or a detail sheet that carries scope.
- Gross vs. net confusion. Not deducting openings, or deducting openings that do not reduce material.
- Double-counting waste. Adding waste to the quantity and again in the unit price.
- Unburdened labor. Pricing labor at base wage without taxes, insurance, and fringes.
- Fixed-percentage general conditions. Ignoring schedule length when pricing time-based costs.
- Markup/margin mix-ups. Applying a markup when you intended a margin, or the reverse.
How F&K Estimatings Can Help
F&K Estimatings, founded by Waqas Malik, prepares quantity takeoffs and cost estimates for general contractors, specialty subcontractors, and developers, organized by CSI MasterFormat with scope-gap review and RFIs for unclear items. Accuracy depends on how complete the drawings are, and we note assumptions where they are not. See our construction estimating service or check pricing.