Proposals · Glossary

What is a bill of quantities?

A bill of quantities, or BOQ, is a document that lists the measured quantities of work and materials needed for a construction project, item by item, so that every contractor prices exactly the same scope. It is usually prepared by a quantity surveyor from the drawings, and the priced BOQ becomes the basis for valuing work and variations.

When five contractors price a project from drawings alone, they measure it five different ways. A bill of quantities removes that variable, so the prices they return can actually be compared.

Indunil Asanka · Co-founder

4 min read · Published 21 October 2026

A bill of quantities against a quote and a schedule of rates
Document	Who measures	What is priced	Use
Bill of quantities	The client's quantity surveyor	Rates against fixed quantities	Competitive tendering on larger projects
Quote	The contractor	A lump sum or lines for the job	Most small and medium jobs
Schedule of rates	Nobody up front	Rates only, quantities measured later	Maintenance and repeat work
Itemised invoice	The contractor, after the work	What was supplied	Billing for work done

What a BOQ contains

A BOQ starts with preliminaries, the site setup, supervision and general costs, then lists the work trade by trade or element by element: excavation, concrete, masonry, framing, roofing, finishes, services. Each item has a description, a unit such as cubic metres, square metres, linear metres or number, and a quantity measured from the drawings. Contractors fill in a rate for each item, which multiplied by the quantity gives the amount, and the amounts total to the tender price. Measurement follows a published standard so that everyone measures the same way. In the UK and many other countries that is the RICS New Rules of Measurement, where NRM 2 covers detailed measurement for building works; Australia and New Zealand have their own institutes of quantity surveyors.

How it is used after the tender

Once a contract is let, the priced BOQ becomes a pricing tool. Progress claims can be valued by measuring the quantities completed and applying the contractor's rates. Variations can be valued the same way, using the rates for similar items. If the actual quantity differs from the measured quantity, many contracts remeasure and adjust, so the client pays for what was really built. That makes a BOQ valuable well beyond the tender, as long as it was measured carefully in the first place.

When a BOQ is worth preparing

BOQs are standard on larger commercial and public projects where several contractors tender and the client wants comparable prices. They cost money to prepare, so small residential jobs rarely have one. For smaller work, a detailed specification and a priced quote with an itemised breakdown achieve much of the same comparability. A BOQ is most useful when the design is complete; on an incomplete design, many items become provisional quantities or provisional sums.

Common mistakes

Contractors sometimes price a rate without reading the item description, missing that it includes extra work. Others load the rates of early items to improve cash flow, which can backfire if quantities change. Clients sometimes issue a BOQ measured from unfinished drawings, which creates variations and claims later. And arithmetic errors in a priced bill, a rate times a quantity that does not equal the amount, need a clear rule in the tender documents about which figure governs.

Where it shows up in the product

The pricing table in the proposals module has the columns a priced BOQ needs to return: Item, Qty, Unit price, Tax, Discount and Amount, and each item can carry a unit label and a group label for the trade or element. Price hints in the brief are authoritative, so the rates and quantities you give become items at exactly those figures. A large bill can run up to 200 items, though the AI writes at most 40 when it drafts the table.

Questions people ask

Who prepares a bill of quantities?

Usually a quantity surveyor engaged by the client or the design team, working from the drawings and specification and following a measurement standard. On some design and build projects, the contractor prepares its own quantities instead. Either way, the measurement should be checked, because errors flow straight into the price.

Is a bill of quantities part of the contract?

Often yes. On many traditional construction contracts, the priced bill forms part of the contract documents and is used to value progress and variations. Whether quantities are fixed or remeasurable depends on the contract wording, which decides who bears the risk if the measured quantities turn out wrong.

What is a provisional quantity in a BOQ?

It is an item whose quantity cannot be measured accurately yet, such as rock excavation before the ground is tested. The contractor prices a rate against the estimated quantity, and the final amount is adjusted once the real quantity is measured. It works much like a provisional sum, but with a priced rate.

Do small builders need a bill of quantities?

Rarely. Small residential work is usually priced from drawings and a specification with a lump sum or itemised quote. Some small builders still measure their own quantities internally, which is good practice for accurate pricing, even if no formal BOQ is ever issued to the client.

How is a BOQ different from a materials list?

A materials list counts things to buy. A bill of quantities describes measured work, which includes labour, plant and materials in each item, so a rate for laying a square metre of tiles covers the tiles, adhesive, grout and labour. That makes it a pricing document rather than a shopping list.

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Sources

Written and checked by the OneCraft team. Last checked 21 October 2026.