Preambles to Bills of Quantities & Tender.
A bill of quantities is a document used in tendering in the construction industry in which materials, parts, and labor (and their costs) are itemized. It also (ideally) details the terms and conditions of the construction or repair contract and itemizes all work to enable a contractor to price the work for which he or she is bidding. The quantities may be measured in number, area, volume, weight, or time. Preparing a bill of quantities requires that the design is complete and a specification has been prepared.
The practice historically of estimating building costs in this way arose from non-contractual measurements, taken off drawings to assist tenderers in quoting lump sum prices.
Bill of quantities is prepared by quantity surveyors and building estimators, and Indeed the bill of quantities was the raison dêtre for the development of quantity surveying as a separate profession.
The bill of quantities is issued to tenderers for them to prepare a price for carrying out the construction work. The bill of quantities assists tenderers in the calculation of construction costs for their tender, and, as it means all tendering contractors will be pricing the same quantities (rather than taking-off quantities from the drawings and specifications themselves), it also provides a fair and accurate system for tendering.