What is estimating in construction?
Estimating is the work of forecasting what a construction project will cost to build, line by line, so a contractor can set a price and a budget. The estimator measures quantities, prices labor, material, equipment, and subcontracts, then adds general conditions, overhead, contingency, and profit. Bidding differs: it is the business decision about what price to submit.
Construction estimating turns drawings, specs, and site conditions into a number. The estimator measures quantities, prices labor, material, equipment, and subcontracts, adds general conditions, overhead, contingency, and profit, and produces a price for the bid or proposal. Done well, the estimate also becomes the first budget for the job, coded the same way the field will track cost.
Types of estimates
| Stage | Based on | Typical use |
|---|---|---|
| Conceptual or order of magnitude | Square foot or unit costs from past jobs | Owner feasibility, go/no-go |
| Schematic or design development | Partial drawings and assumptions | Budget checks, early GMP talks |
| Detailed or bid | Complete drawings, takeoffs, sub quotes | Hard bids, lump sum contracts |
| Change order estimate | Revised scope only | Pricing a change |
The estimating process on a real job
An estimator at a commercial interiors contractor has three bids due Friday. Take one: a $650,000 office renovation.
- Read the bid package, addenda, and specs. Note the bid form, the bond requirement, and the scope split.
- Do the quantity takeoff: linear feet of wall by type, square feet of ceiling, door counts.
- Price self-performed work using production rates from past jobs, for example labor hours per 100 square feet of hung board.
- Send scopes to subs and suppliers, then level the bids so every number covers the same scope.
- Price general conditions: supervision, temporary facilities, cleanup, permits, insurance.
- Add markup and contingency, review with an owner or senior estimator, and write clarifications and exclusions.
In this example, takeoff shows 9,800 square feet of new partitions. At a historical 2.1 labor hours per 100 square feet and a $64 burdened rate, framing and board labor is about 206 hours and $13,200. A gut check against two recent similar jobs confirms the number is in range. That kind of check catches the typo that turns 9,800 into 98,000. The same discipline applies to sub numbers: a quote far below the others usually means missing scope.
Common estimating mistakes
- Copying last job's production rates without checking conditions (height, access, occupied building, night work).
- Scope gaps between subs, where a task falls between two scopes and nobody prices it. See scope gap.
- Missing addenda. One late addendum can change the price.
- Lowballing general conditions to win, then losing money every week the job runs long.
- Not feeding actual job results back into the database, so the same miss repeats.
Related terms
Estimating connects to takeoff, bid day, markup, value engineering, and precon. For a full walkthrough, see how to estimate a construction project or start from the construction estimate template. Smart Business Automator's estimate to project handoff automation carries the estimate into the job budget so the field tracks against the same lines.
Frequently asked questions
What is the difference between estimating and bidding?
Estimating figures out what the work will cost. Bidding is the business decision about what price to submit, which adds strategy, markup, and terms on top of the estimate.
How accurate should a construction estimate be?
It depends on the stage. Conceptual estimates have wide ranges; a detailed bid estimate should be close enough to protect your margin. Track your own variance from actual to know where you stand.
What is a unit cost in estimating?
The cost for one unit of work, such as dollars per square foot of slab or per linear foot of pipe, including labor, material, and equipment.
Should general conditions be estimated separately?
Yes. Time-based costs like supervision and temporary facilities depend on duration, not quantities, so price them from the schedule.
