- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 09 Aug 2018
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.
 Find out more
 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.
- 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.
Featured articles and news
What to bear in mind when claiming damages in construction.
How do we achieve sustainable clean-water infrastructure for all?
What you should know when appointing an architect.
A brief history plus some new developments.
How computational fluid dynamics (CFD) helps building design.
The Hong Kong Harbour Area Treatment Scheme (HATS).
'Expressions of interest' for construction contracts.
Dame Judith Hackitt confirmed as keynote speaker – one year on from the Hackitt Report. Save £100 on tickets.
House of Lords committee calls for investment in housing, transport, education and infrastructure.
Supporting assets that are crucial to achieving business goals. Free download.
We've created a custom search engine for the construction industry. Let us know what you think.