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
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation which closes 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
Places of Worship in Britain and Ireland, 1929-1990. Book review.
The emancipation of women in art.
CIOB Construction Manager of the Year 2025
Just one of the winners at the CIOB Awards 2025.
Call for independent National Grenfell oversight mechanism
MHCLG share findings of Building Safety Inquiry in letter to Secretary of State and Minister for Building Safety.
The Architectural Technology Awards
AT Awards now open for this the sixth decade of CIAT.
50th Golden anniversary ECA Edmundson awards
Deadline for submissions Friday 30 May 2025.
The benefits of precast, off-site foundation systems
Top ten benefits of this notable innovation.
Encouraging individuals to take action saving water at home, work, and in their communities.
Takes a community to support mental health and wellbeing
The why of becoming a Mental Health Instructor explained.
Mental health awareness week 13-18 May
The theme is communities, they can provide a sense of belonging, safety, support in hard times, and a sense purpose.
Mental health support on the rise but workers still struggling
CIOB Understanding Mental Health in the Built Environment 2025 shows.
Design and construction material libraries
Material, sample, product or detail libraries a key component of any architectural design practice.
Construction Products Reform Green Paper and Consultation
Still time to respond as consultation closes on 21 May 2025.
Resilient façade systems for smog reduction in Shanghai
A technical approach using computer simulation and analysis of solar radiation, wind patterns, and ventilation.