Firm bill of quantities
A bill of quantities (BoQ) is a document prepared by a cost consultant that provides project-specific measured quantities of the items of work identified by the drawings and specifications in the tender documentation. The quantities may be measured in number, length, area, volume, weight or time. A bill of quantities is issued to tenderers for them to prepare a price for carrying out the works.
The more precisely the work in a bill of quantities can be measured and described (i.e. the ‘firmer’ it is) the more accurate tenderers’ prices should be, the easier it will be to control costs and the fewer variations will be necessary. The process of identifying elements of construction works that can be measured and priced is known as 'taking off'.
A firm bill of quantities can be prepared when the design is complete, a detailed specification has been prepared and quantities can be accurately calculated. If there were no changes to the project requirements following the preparation of a firm bill of quantities, then the tenderer’s priced bill of quantities would be the same as the final cost of the contract. In practice of course there are always changes.
Where it is not possible to prepare a firm bill of quantities at the time of tendering, an approximate bill of quantities (or notional bill of quantities) might be prepared. This might be necessary, for example, if the design is relatively complete, but exact quantities are not yet known. However, this will tend to result in more variations during construction and so less price certainty when the investment decision is made.
Approximate bills of quantities can also be used during the design process as a tool for controlling design development.
[edit] Related articles on Designing Buildings Wiki
- Advantages of a bill of quantities.
- Approximate bill of quantities.
- Approximate bill of quantities vs approximate quantities cost plan.
- Approximate cost plan.
- Approximate quantities.
- Bill of quantities.
- Bill of quantities software.
- Common mistakes in bill of quantities.
- Cost plans.
- How to take off construction works.
- New Rules of Measurement.
- Priced bill of quantities.
- Quantity surveyor.
- Taking off.
- Types of bill of quantities.
- Working up construction works.
Featured articles and news
Retrofit 25 – What's Stopping Us?
Exhibition Opens at The Building Centre.
Types of work to existing buildings
A simple circular economy wiki breakdown with further links.
A threat to the creativity that makes London special.
How can digital twins boost profitability within construction?
The smart construction dashboard, as-built data and site changes forming an accurate digital twin.
Unlocking surplus public defence land and more to speed up the delivery of housing.
The Planning and Infrastructure Bill
An outline of the bill with a mix of reactions on potential impacts from IHBC, CIEEM, CIC, ACE and EIC.
Farnborough College Unveils its Half-house for Sustainable Construction Training.
Spring Statement 2025 with reactions from industry
Confirming previously announced funding, and welfare changes amid adjusted growth forecast.
Scottish Government responds to Grenfell report
As fund for unsafe cladding assessments is launched.
CLC and BSR process map for HRB approvals
One of the initial outputs of their weekly BSR meetings.
Architects Academy at an insulation manufacturing facility
Programme of technical engagement for aspiring designers.
Building Safety Levy technical consultation response
Details of the planned levy now due in 2026.
Great British Energy install solar on school and NHS sites
200 schools and 200 NHS sites to get solar systems, as first project of the newly formed government initiative.
600 million for 60,000 more skilled construction workers
Announced by Treasury ahead of the Spring Statement.
The restoration of the novelist’s birthplace in Eastwood.
Life Critical Fire Safety External Wall System LCFS EWS
Breaking down what is meant by this now often used term.
PAC report on the Remediation of Dangerous Cladding
Recommendations on workforce, transparency, support, insurance, funding, fraud and mismanagement.
New towns, expanded settlements and housing delivery
Modular inquiry asks if new towns and expanded settlements are an effective means of delivering housing.