Bill of Quantities
A formal, itemized document listing the quantities of every scope of work in a construction project, used as the basis for pricing and contract.
Definition
A bill of quantities (BOQ) is a formal, itemized document that lists every scope of work in a construction project along with the quantity, unit of measure, and (once priced) the unit rate and total amount for each item. It is prepared from the drawings and specifications and serves as the structured pricing basis for both bidding and contract administration.
BOQs are the standard pricing document on most international construction contracts and on public projects in the UK, Middle East, Australia, and much of Asia. In North America, the schedule of values plays a similar role on lump-sum contracts.
How bill of quantities is used in estimating
During bidding, the BOQ is issued to all bidders with quantities filled in but the unit rate column blank. Each contractor enters their unit rates, the totals extend automatically, and the bottom line is the bid price. Because every bidder is pricing the exact same quantities, the owner can compare bids on a true apples-to-apples basis.
After award, the BOQ becomes a contract document. Progress payments are calculated against the BOQ — measure what has been installed, multiply by the contract unit rate, and certify payment for that amount. Variations and change orders are also priced using the BOQ unit rates wherever the new work matches an existing item, which prevents pricing disputes mid-project.
When to apply a BOQ
Use a BOQ on any project where quantities may vary during construction, on most public-sector work, and on international contracts that follow FIDIC or similar standard forms. BOQs are less common on simple lump-sum residential work in the United States, where a schedule of values is usually sufficient. On design-build projects with rapidly changing scope, a BOQ may be replaced by an open-book cost-plus arrangement instead.
Frequently asked questions
Q.What is the difference between BOQ and bill of materials?
A BOQ covers all scopes of work including labor-driven items like excavation hours or scaffolding rental. A bill of materials only lists physical materials. The BOQ is broader and is used contractually, while a bill of materials is mostly a procurement document.
Q.Who prepares the bill of quantities?
On traditional contracts the BOQ is prepared by a quantity surveyor working for the owner or design team and issued to bidders. On design-build or contractor-led projects, the contractor’s estimating team prepares the BOQ from their own takeoff.
Q.What goes in each line of a BOQ?
A description of the work, the unit of measure, the quantity, the unit rate, and the extended amount (quantity multiplied by unit rate). Many BOQs also include a reference to the relevant specification section.
Q.Is a BOQ legally binding?
Yes — once executed as part of the contract, the priced BOQ binds the contractor to those unit rates and the owner to those quantities (subject to remeasurement clauses). It is one of the documents that governs payment and variations.
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