Bill of quantities

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A bill of quantities (BOQ) is a document used in tendering in the construction industry / supplies 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, length, area, volume, weight or time. Preparing a bill of quantities requires that the design is complete and a specification has been prepared. The bill of quantities is issued to tenderers for them to prepare a price for carrying out the works. 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


Bills of quantities are prepared by quantity surveyors and building estimators, and "Indeed the bill of quantities was the reason for the development of quantity surveying as a separate profession." COBRA The international operations or trades used in construction. As the rates for materials and labour change due to inflation, these books are frequently republished..

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.

There are different styles of bills of quantities, mainly the Elemental BOQ and Trade Bills.

Contingency sum[edit]

A Contingency sum is an item found within a Bill of quantities (BoQ).

The item refers to unforeseeable cost likely to be incurred during the contract.

There are two types of contingency sum. The first refers to a specific item, e.g., 'additional alterations to services when installing said shower unit', where an item for alterations to existing services is not contained within the BoQ but some work is envisaged.

The second type of sum is where money can be allocated to any item, within the BoQ, in the same way as the above example or used as 'additional work to be undertaken by the contractor, at the request of the contract administrator'.

The first is usually approximated by the client’s PQS and the second by the contractors QS (or commercial manager).

Additional requirements is referred as Bill of materials (BOM).

See also[edit]

A Bill of Quantities does in fact consider all costs and is transparent in relations to all costs. Where information is missing at the time, sums based on ad hoc schedules or known rates will be entered, but this will of course depend on the contract being used. Traditional routes, where time is not so much an issue add better cost certainty. From inception to completion and beyond Bills of Quantities cover all aspect of work and this includes all work, materials and any cost related aspects supplied by the contractor. This is done in the preliminary stages of the Bill and it is then up to the contractor to enter rates against the items mentioned. (The description previously edited here is misleading and untrue.)



  • Seeley IH. (1998). Building Quantities Explained 5th Revised edition, Macmillan ISBN 978-0-333-71972-5
  • Seeley IH. (1997). Quantity Surveying Practice, 2nd Revised Macmillan; ISBN 978-0-333-68907-3
  • Lee S. Trench W. Willis A. (2005) Elements of Quantity Surveying. 10th Edition WileyBlackwell; ISBN 978-1-4051-2563-5
  • Ashworth A. Hogg K. (2007). Willis’s Elements of Quantity Surveying 12 Rev Ed edition Blackwell Publishing. ISBN 978-1-4051-4578-7