Quantity take-off
The process of reading project drawings and specifications to count, measure, and list all materials, components, and work items required to complete a project. The output feeds cost estimates, bills of quantities, and procurement planning.
A quantity take-off (often abbreviated to QTO) is the process of reading through project drawings and specifications to count, measure, and list every material, component, and item of work required to complete a project. The term comes from the original practice of physically "taking off" items from drawings - recording lengths, areas, volumes, and unit counts until the full scope has been captured.
In construction, a quantity surveyor or estimator typically carries out the take-off during the pre-construction phase. The output feeds directly into cost estimates, bill of quantities preparation, tender submissions, and materials procurement.
How a Quantity Take-Off Connects to Downstream Work
Once quantities are established, they are priced to produce a cost estimate. The same figures then drive purchase orders and RFQs to suppliers once the project is confirmed. Accuracy at the take-off stage matters because under-measured quantities lead to material shortages and programme delays, while over-measured quantities cause unnecessary spend on materials that may need to be returned or written off.
The distinction between a quantity take-off (QTO) and a material take-off (MTO) is worth noting. A QTO covers all measurable work items - including labour and plant - based on net in-place quantities from the drawings. An MTO focuses specifically on materials for procurement, often expressed in gross quantities that include allowances for waste and cutting.
Digital Take-Offs
Estimating software and BIM tools now allow quantities to be extracted directly from 3D models, reducing manual measurement and making it faster to update take-offs when drawings change during design development or after a variation is issued.