Quantity take-offs (QTO) are a detailed measurement of materials and labor needed to complete a construction project. They are developed by an estimator during the preconstruction phase. These measurements are used to format a bid on the scope of construction. Estimators review drawings, specifications, and models to find these quantities. Experienced estimators have developed procedures to help them quantify their work. Many programs have been developed to aid in the efficacy of these processes.
As defined by Holm, Schaufelberger, Griffin and Cole:
The QTO is the most tedious and time-consuming part of the lump-sum estimating process. An extensive search is made for the measurements are needed to calculate the various valuable quantities that will be used for construction and pricing in a later phase of the estimating faster process.