Bill of Quantities (BOQ)

A bill of quantities (BOQ) is one of the most important tender documents in construction procurement. It standardises the pricing basis for competing contractors, removes the cost and uncertainty of each bidder measuring the works independently, and creates a detailed financial framework for contract administration throughout the project.

What is a Bill of Quantities (BOQ)?

A BOQ is prepared by a quantity surveyor (QS) or cost consultant on behalf of the contracting authority, usually after the design has reached a sufficient level of detail. It lists every discrete item of work required to complete the project, described in accordance with a standard method of measurement, with quantities for each item. Contractors price each item by inserting a rate; multiplying rate by quantity gives the item value, and the total of all items gives the contract sum.

In the UK the standard method of measurement for building works is the New Rules of Measurement (NRM2), published by the Royal Institution of Chartered Surveyors (RICS). Civil engineering work traditionally uses the Civil Engineering Standard Method of Measurement (CESMM). In many EU member states, equivalent national measurement standards apply.

The BOQ enables direct comparison of tenders because every bidder prices the same quantities. It also provides the basis for valuing variations: if the scope changes, the agreed rates in the BOQ are used to calculate the cost of additional or omitted work.

Provisional sums are typically included in the BOQ for elements of work that cannot be fully defined at tender stage. These are distinguished from firm quantities and are remeasured or instructed separately during the works.

A schedule of rates is a related document used when quantities cannot be determined in advance, such as for term maintenance contracts, where the BOQ structure exists but without pre-agreed quantities.

The BOQ is used in JCT Standard Building Contracts (the "with quantities" form), FIDIC Red Book contracts, and NEC Option B contracts.

Why it matters for bidders

The BOQ is both an opportunity and a risk. Bidders who price rates accurately relative to their actual costs gain a reliable picture of project profitability. Unbalanced pricing (loading rates on early items and reducing them on later items to improve cash flow) is a recognised but risky strategy, as it creates exposure if the contract is terminated early or if variations reduce the quantities of over-priced items.

Contractors should also review the quantities themselves. Errors in the BOQ that favour the contractor may not survive the measurement process; errors that disadvantage the contractor can be corrected, but only if raised promptly.

Example

A Swedish county council procures a new school building. The QS prepares a BOQ under the Swedish AB 04 contract conditions with approximately 2,400 line items covering groundworks, concrete, steelwork, cladding, M+E services, and finishings. Three contractors submit tenders. The BOQ rates submitted by the winning contractor become the agreed schedule of rates for valuing all instructed variations during the 22-month contract.

Frequently Asked Questions

Who is responsible for errors in the BOQ?

Under most standard forms, the employer (contracting authority) takes responsibility for errors in the BOQ quantities. If a quantity is understated, the contractor is generally entitled to be paid for the actual work done. Bidders who spot errors should raise them before submitting, as the rules vary between contract forms and jurisdictions.

What is the difference between a BOQ and a schedule of rates?

A BOQ includes both item descriptions and quantities, giving each item a value. A schedule of rates includes only item descriptions and rates, without fixed quantities. The schedule of rates is used where the volume of work is unknown in advance and payment is made on a measured basis.

Is a BOQ always required in public procurement?

No. Design-and-build contracts and lump sum contracts often use an activity schedule or contractor's proposals rather than a BOQ. The BOQ is most appropriate where the design is employer-led and sufficiently detailed to allow accurate measurement before tender.