Quantity Takeoff
The process of measuring and counting exact quantities of materials, such as cubic yards of concrete, linear feet of wall, or number of doors, directly off the architectural and engineering drawings, forming the foundation every cost estimate is built on.
Why it matters
A bid is only as accurate as the quantities it's priced against. Get the takeoff wrong, say by miscounting linear feet of drywall or missing a wall entirely, and every downstream number in the estimate is wrong too, no matter how accurate the unit pricing is.
On a real project
An estimator uses takeoff software to measure every wall on a floor plan, generating an exact linear footage of drywall partition, which then gets multiplied by a per-linear-foot cost to build that portion of the estimate.
Who this matters most to
An Estimator performs the quantity takeoff as one of the first and most fundamental steps of building a bid, often the single most time-consuming part of estimating a large project. A Senior Estimator spot-checks takeoffs on major cost items before a bid goes out, since a takeoff error on a big-ticket item like concrete can be expensive to catch after the fact.
Where this goes wrong
An estimator's takeoff software misreads a drawing revision and counts an entire wing of a building's floor area only once instead of twice, since the plans showed it as a mirrored duplicate. The resulting bid is missing roughly half the actual square footage of work, and the error isn't caught until well after the contract is signed.