What is a construction takeoff?
A construction takeoff is the measured list of quantities in a set of plans and specs: counts of doors and fixtures, linear feet of wall and conduit, square feet of slab and drywall, cubic yards of concrete and soil. The estimator prices those quantities to build the estimate, so a takeoff error becomes a bid error.
What does a takeoff measure?
| Measure | Unit | Examples |
|---|---|---|
| Count | EA | Doors, light fixtures, plumbing fixtures, rooftop units |
| Length | LF | Partitions, curbs, conduit, piping, base |
| Area | SF or SY | Slab on grade, drywall, ceilings, roofing, paving |
| Volume | CY | Concrete, excavation, fill |
| Weight | TON or LB | Structural steel, reinforcing steel |
Takeoff or estimate: what is the difference?
The takeoff answers "how much". The estimate answers "what will it cost", by applying material prices, labor productivity, equipment, and markup to those quantities. Organizing both by CSI MasterFormat lets the same lines flow into sub bid comparison and the schedule of values.
How is a takeoff done, step by step?
- Confirm the drawing set. Use the latest issue with every addendum; note the revision of each sheet.
- Read the specs with the drawings. The spec decides the product, the drawing decides the quantity.
- Set up by CSI section. One line per MasterFormat section and assembly, with units.
- Measure sheet by sheet, marking what has been counted so nothing is counted twice.
- Add waste and laps where the trade prices them, and record the factor.
- Check against a second source: a quick area check, last project's ratios or another estimator.
What are the most common takeoff errors?
| Error | Cause | Effect |
|---|---|---|
| Counts from an old revision | Addendum sheets not swapped in | Under-bid on the revised scope |
| Double counting at boundaries | Same conduit taken off in Division 26 and 27 | Inflated price, lost bid |
| Spec and drawing mismatch | Drawings read without the specs | Wrong product priced; RFI after award |
| Scope assumed from the last job | Inclusions not checked against this spec | Scope gap after award |
| Wrong labor basis | Open-shop productivity and rates on prevailing wage work | Labor under-priced |
Manual, digital or automated takeoff?
| Method | How it works | Watch out for |
|---|---|---|
| Paper and scale | Printed sheets, scale ruler, highlighters | Slow; hard to check or update |
| On-screen digital takeoff | Estimator clicks areas, lines and counts on PDF sheets | Still manual; accuracy depends on the operator |
| Automated from PDF | AI proposes quantities from vector or scanned plans for the estimator to check | Every quantity still needs review; unusual assemblies need judgment |
Contractors expect this to change. In the AGC and NCCER 2026 Workforce Survey, 67 percent of contractors said they expect AI's biggest impact in their own company on estimating and bidding (AGC and NCCER, 2026).
Where does BAU AI fit?
Theo takes quantities off 2D PDF plan sets (areas, lengths and counts), maps them to CSI divisions, and marks each quantity on its sheet so the estimator can check it, then compares them with your estimate. Theo is not part of the paid plans yet, and DWG and DXF files are on the roadmap only. The estimator approves every number.
Frequently asked questions
What is a quantity takeoff?
The measured list of quantities in a set of plans and specs, organized by item and unit, ready for the estimator to price.
What is the difference between a takeoff and an estimate?
A takeoff measures quantities. An estimate prices them with material, labor, equipment and markup. The takeoff comes first.
Why organize a takeoff by CSI MasterFormat?
Specs, sub bids and schedules of values in US commercial work use MasterFormat numbering. A takeoff in the same order lines up with each of them without translation.
Does BAU AI do quantity takeoff?
Yes. Theo takes quantities off 2D PDF plan sets and marks each one on its sheet for the estimator to check. It is not included in the plans yet.
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