A beginner's guide to construction quantity takeoffs — what they are, how they're produced, the different methods used, and why accuracy is so critical.
If you're new to construction estimating, the term "quantity takeoff" may be unfamiliar. Even if you've been in the industry for years, you may not have seen the full picture of how professional takeoffs are produced. This guide covers everything you need to know.
What Is a Quantity Takeoff?
A quantity takeoff (QTO) is the process of measuring and listing all the materials required to complete a construction project, based on a review of the project drawings and specification. The resulting document — typically a spreadsheet or schedule — forms the basis for material ordering and cost estimation.
The term comes from the physical act of "taking off" quantities from drawings: measuring dimensions and counting items to produce a list of what the project actually requires.
Why Quantity Takeoffs Matter
Without an accurate takeoff, any cost estimate is essentially guesswork. The takeoff is the foundation that everything else — material costs, labour hours, plant requirements — is built upon. An error at the takeoff stage compounds through the entire estimate.
For contractors, an accurate takeoff enables:
- Competitive tendering without excessive contingency
- Reliable material ordering with minimum waste
- Subcontractor management based on known scope
- Change order management with a clear baseline
Methods of Quantity Takeoff
Manual Takeoff
The traditional method involves measuring printed or plotted drawings with a scale rule, recording dimensions by hand or into a spreadsheet. This is time-consuming and prone to arithmetic errors but remains common for smaller projects.
Digital Takeoff
Digital takeoff software (such as Bluebeam, PlanSwift, or Countfire) allows estimators to measure dimensions directly from PDF drawings on screen, automatically converting measurements to areas, lengths, and volumes. This is faster and more accurate than manual measurement.
BIM Takeoff
For projects using Building Information Modelling (BIM), quantities can be extracted directly from the 3D model using software such as Revit or Navisworks. This is the most accurate method but requires that the model has been built with sufficient detail.
Concrete Takeoff Specifically
A concrete quantity takeoff begins with identifying all concrete elements from the drawings, then calculating volumes for each. The estimator must also note:
- Mix specification for each element
- Reinforcement requirements
- Formwork areas
- Finishing requirements
- Access conditions
This information feeds directly into the cost estimate.
Using a Professional Takeoff Service
For contractors without dedicated estimating resource, outsourcing takeoffs to a specialist service like Britespire Construct is a cost-effective alternative to maintaining in-house capability. Professional takeoff services typically produce results faster and more accurately than most in-house teams, at a fixed, transparent fee.