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Estimating & Biddingaka: QSaka: bill of quantities

Quantity Survey

In Plain English

A complete measurement of all the work and materials needed for a project, used to calculate costs.

Definition

A quantity survey is the systematic measurement and listing of all materials, labor, and work items required to complete a construction project, used to prepare a bill of quantities or detailed estimate. Quantity surveyors are professionals who specialize in cost management and quantity measurement. The term is more common in the UK and Commonwealth countries.

Why It Matters in Bidding

The quantity survey is the backbone of an accurate estimate — every material, labor, and equipment cost ties back to measured quantities. Errors in the survey compound through markup and contingency, producing a bid that is either uncompetitive or unprofitable. Consistent, documented quantities also let a GC defend its number during scope review and price addenda changes quickly.

Example

Before pricing a mid-rise apartment shell, an estimator performs a quantity survey from the drawings, measuring every cubic yard of concrete and ton of rebar to build the takeoff that feeds the bid.

Related Terms

Quantity TakeoffTake-OffEstimatorDetailed Estimate

Frequently Asked Questions

They overlap heavily. In U.S. practice, takeoff is the common term for measuring quantities from drawings, while quantity survey is the broader, more formalized term used internationally and often paired with a bill of quantities. Both produce the measured basis an estimator prices to assemble a bid.
Because pricing only multiplies quantities by unit costs, a survey error scales straight into the bottom line. Overstated quantities lose work to lower bidders; understated quantities win the job but erode margin. A clean survey also speeds repricing when addenda revise scope, keeping the bid responsive under deadline pressure.
The dedicated quantity surveyor role is far more common in the UK and Commonwealth markets. In the U.S., similar measurement and cost-management work is performed by estimators and cost engineers within GCs, subs, or consulting firms, though the underlying discipline of systematic measurement is the same.

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