A step-by-step guide to construction estimates for contractors: types of estimates, scope review, quantity takeoff, labor, materials, equipment, subcontractors, overhead, contingency and profit, plus how to learn from every job.
| Type | When it is used | Accuracy |
|---|---|---|
| Order of magnitude / rough | Early feasibility, very little design | Lowest |
| Square foot or unit cost | Early budgeting using cost per unit | Low to moderate |
| Assembly or system | Design development, priced by building systems | Moderate |
| Detailed / unit price | Bidding, priced from a full takeoff | Highest |
Most contractors preparing a bid work from a detailed estimate. The more design information is available, the more precise the estimate can be, so match your method to the stage of the project. Early-stage numbers should always be labeled as rough so clients do not treat them as a price.
Read the plans, specifications, addenda and contract terms carefully. List what is included, what is excluded and what is unclear. Visit the site if you can: access, storage space, existing conditions and local factors all affect cost. Submit questions before the deadline rather than guessing. A pre-construction meeting later confirms the details with the client.
A takeoff counts and measures everything the job needs: concrete volumes, linear feet of framing, square feet of drywall, number of fixtures and so on. Work trade by trade or by building system, keep your measurements organized and note the drawing references. Add a waste factor for materials based on your own experience with each material and method.
Get current prices from suppliers rather than relying on old numbers, especially for materials with volatile prices. Include delivery, taxes and any special order lead times. For long projects, consider whether prices may change before you buy and how your contract handles that.
Labor is often the most uncertain part of an estimate. Estimate the hours each task needs using your own production rates from past jobs, adjusted for site conditions, crew experience and season. Multiply hours by the burdened labor rate, which includes wages plus payroll taxes, workers’ compensation, benefits and other employer costs. On public projects, prevailing wage rules may apply. The labor burden calculator, job labor cost calculator and how to calculate labor cost help.
Overhead covers company costs that are not tied to a single job, such as office rent, vehicles, administration and software. Allocate a share to each job. Contingency covers known risks, such as unclear scope or difficult conditions; it is not a place to hide errors. Profit is what the business earns for taking on the work. Use the overhead rate calculator and profit margin calculator to check your numbers, and remember that markup and margin are not the same thing.
Small contractors often estimate with spreadsheets, and that can work well if the templates are consistent. As volume grows, dedicated estimating and takeoff software can speed up measurements, keep cost databases current and produce cleaner proposals. Whatever tool you use, the inputs matter most: accurate quantities, current prices and production rates based on your own crews. Keep a standard checklist of cost items so nothing is forgotten from one bid to the next, and store each estimate with its assumptions so you can compare later.
The most valuable data for future estimates is your own. Track actual labor hours by task and job, compare them with the estimate and update your production rates. Record material waste, change orders and delays. Over time, this job cost history becomes your competitive advantage. Accurate time tracking by job and cost code is the foundation.
When your own crews perform the work, the estimate is only as good as your production rates. Break each scope into tasks small enough to measure, such as setting forms, placing concrete or hanging a set amount of drywall, and record the crew size and hours actually spent on each. Adjust for factors that slow work down: working at height, tight access, occupied buildings, weather, overtime fatigue and learning curves on unfamiliar work. Keep separate rates for different crew experience levels if they differ significantly.
A small remodeling contractor kept losing money on bathroom jobs despite winning bids. After tracking actual labor hours by task for several jobs, the owner found tile work was taking much longer than his estimates assumed and that he had not included labor burden. He updated his production rates and switched to burdened labor rates. His bids rose slightly, he won fewer of the lowest-priced jobs, but the jobs he won were profitable.
A low bid wins nothing if the job loses money. Instead of cutting your estimate to match a competitor, compete on what the client values: clear scope, reliable schedules, quality and communication. Present your proposal clearly, explain your assumptions and exclusions and follow up promptly. Our guide on how to get construction contracts covers finding and winning work.
EZTime gives construction crews a mobile time clock with GPS and tracks hours by job and client, so you can compare actual labor with your estimates. Foremen run crew schedules, capture site tasks with photo proof and log job expenses. See construction.
A prediction of a project’s total cost, used to set a bid price or budget.
Materials, labor, equipment, subcontractors, permits, general conditions, overhead, contingency and profit.
A count and measurement of all the materials and work items a project needs, taken from the plans.
Use your own production rates from past jobs and multiply hours by a burdened labor rate.
Track actual costs and hours by job, compare them with estimates and update your rates.
EZTime tracks crew hours by job with GPS clock-ins, so your next estimate is based on real data. Pricing starts from $2 per employee a month, and the smallest accounts pay a $20 monthly minimum.