Bill of Quantities (BOQ) in Construction: A Complete Guide for UK Contractors, Real Estate Developers and Owners

A Bill of Quantities (BOQ or BQ) is an itemized list of the materials, labor and work stages needed to complete a construction project, prepared by a quantity surveyor or cost consultant from architectural, structural and M&E drawings and specifications. Contractors use it directly to price and submit accurate tender bids. Real estate developers and owners rely on it, through their quantity surveyor, to set and track the project budget.

In UK construction, it is issued at tender stage so every bid prices the same defined scope, and it typically follows standards such as the RICS New Rules of Measurement (NRM2) for building work, or the ICE Civil Engineering Standard Method of Measurement, Fourth Edition (CESMM4) for civil engineering. Once a contract is signed, the same document underpins interim payments, variations and the final account.

1. Purpose of a Bill of Quantities 

A Bill of Quantities performs a different function for contractors, real estate developers and owners at each stage of a project, from tender through to final account:

• Fair tendering — a BOQ gives every tendering contractor the same quantified scope to price. Without it, each contractor takes their own measurements from the drawings and prices a different interpretation of the same project. Pricing an identical list of items and quantities makes bids comparable on a like-for-like basis. Measuring the quantities in detail also tends to surface conflicts between drawings that weren’t obvious on a first read, before they reach site.
• Cost certainty — once contractors return their bids, the client’s QS uses the BOQ to produce a detailed, itemized cost breakdown before construction starts. This gives developers and owners a line-by-line, priced basis for the project budget. 
• Payment, variation and final account — the same document values the work as it’s built. Completed quantities are measured on site and priced against the BOQ’s rates to calculate interim payments for contractors. If the design changes, work similar to what’s already in the BOQ is priced using those same agreed rates — only work with no comparable item needs a new rate agreed. At project completion, this record is reconciled into the final account, giving developers and owners a settled cost position and contractors a closed account.

Read also: Construction Cost Value Reconciliation (CVR) Best Practices for Main Contractors

2. UK BOQ Measurement Standards

In the UK, a BOQ for building work is measured according to NRM2 — the RICS New Rules of Measurement — which replaced the earlier SMM7. NRM2 sets out which unit of measurement applies to each type of item (area for plastering, volume for concrete, a count for doors), what is deemed included within a measured item so the same work isn’t priced twice, and what information must appear in each item’s description, and in what order. Civil engineering and infrastructure work — roads, bridges, water and drainage schemes — is measured under CESMM4, the ICE Civil Engineering Standard Method of Measurement, Fourth Edition.

A formal, NRM2-measured bill isn’t produced on every UK project. On Design and Build contracts and BIM-led schemes, some teams work from a digital quantities schedule generated from the model instead. The underlying principle — standardized, comparable measurement — still applies. Only the format changes.

3. Standard Structure and Contents of a BOQ

Under NRM2, a BOQ commonly includes the following:

• Preliminaries — project-wide costs not tied to a specific piece of work: site management and supervision, scaffolding, temporary fencing and security, temporary power, water and welfare facilities.
• Preambles — the quality and workmanship standards contractors must meet, typically referencing specific British Standards or Eurocodes for materials and methods.
• Measured Works — the core of the document: physical construction items broken down by trade or element (excavation, concrete, brickwork, roofing, finishes, services). Each line carries an item reference, description, unit and quantity, with rate and total left for the contractor to complete.
• Provisional Sums — allowances for work that can’t yet be fully defined at tender stage, such as an element still pending final design or ground conditions that can’t be confirmed in advance.
• Prime Cost (PC) Sums — allowances for work or supply that is fully defined but will be carried out by a nominated subcontractor or supplier whose price isn’t fixed at tender, such as a specialist installation or a statutory undertaker’s connection charge.
• Dayworks — agreed hourly rates for labor and material markups, used to price ad-hoc work that falls outside the measured items once construction is underway.

4. Who Prepares and Uses a Bill of Quantities

On the client side, a Quantity Surveyor or cost consultant prepares the BOQ from the architectural, structural and M&E drawings. Larger real estate developers and asset owners often run this in-house through their own QS function. Smaller clients without that expertise typically engage an external Professional Quantity Surveyor (PQS) or cost consultancy to produce it.

On the contractor side, estimators use the BOQ at tender stage to build the bid, entering rates against each item.

Once a contract is awarded, the same document stays in use on both sides. The client’s QS continues to value payments and assess variations through construction. On the contractor’s side, it passes from the estimator to whoever runs commercial control on the project — typically a Quantity Surveyor, Commercial Manager or Contracts Manager — who tracks cost position against the agreed rates for the rest of the build.

5. How to Prepare a Bill of Quantities for a New Building?

Preparing an accurate Bill of Quantities for a new building requires a defined sequence, from finalized drawings through to a checked, tender-ready document:

1. Gather the design information: Collect the architectural, structural and M&E drawings, along with the specifications, and confirm they’re finalized before measuring starts. Unconfirmed or incomplete drawings at this stage cause rework once the take-off is underway.
2. Take off the quantities: Measure each item directly from the drawings, applying the units NRM2 assigns to that type of work — area, volume, length, weight or count.
3. Write the item descriptions: Describe each item with enough detail — material, size, location — that every tendering contractor prices the same scope.
4. Assemble into the BOQ structure: Organize the measured items into Preliminaries, Preambles, Measured Works, Provisional Sums, Prime Cost Sums and Dayworks.
5. Check, then issue for tender: Cross-check the quantities against the drawings and specifications before the BOQ goes out to contractors.

6. Bill of Quantities vs Related Documents

A BOQ works alongside other project documents, each defining a different part of the scope:

Document	What It Defines	Relation to the BOQ
Drawings	The design and layout, produced by the architectural, structural and M&E design teams	The source the BOQ is measured from
Specification	The quality and standard of materials and workmanship	Referenced within the BOQ’s Preambles
Cost Plan	An elemental cost estimate prepared during design	Produced earlier, before drawings are finalized enough to measure a BOQ from

6.1 Bill of Quantities vs Bill of Materials (BOM)

A Bill of Materials (BOM) lists only the materials needed for a piece of work — quantities of specific products or components, used for ordering and procurement. A Bill of Quantities is broader: it covers materials, labor and the total cost of each item, and forms the pricing basis for a construction contract.

A subcontractor might produce a BOM to order steel or fittings for their own package. That BOM doesn’t replace the BOQ their price was based on — it sits underneath it, covering procurement for a single trade package.

Read also: Why Centralised Cost and Contract Management Is the Prerequisite for Effective Commercial Control in Subcontractor-Driven Construction

7. Common Mistakes to Avoid When Creating a Bill of Quantities

These common mistakes recur across BOQ preparation and distort pricing before a single tender comes back:

• Double counting — the same item gets measured more than once, especially when a take-off is split across multiple drawing packages or more than one estimator. It inflates quantities and distorts every bid built on them.
• Wrong unit of measurement — pricing concrete by area when it should be measured by volume makes the rate meaningless and the total wrong, however carefully it was calculated. 
• Omitted items — temporary works, testing and commissioning, and site protection sit in supporting documents, separate from the main drawings, which makes them easy to miss during take-off. 
• Copied Preliminaries — reusing a previous project’s Preliminaries without adjusting them to the site adds costs the current project doesn’t need and misses requirements it does. 
• No independent review — a second quantity surveyor or estimator checking the take-off catches errors the person who produced it won’t see in their own work. Skipping this step is how the other four mistakes reach tender unnoticed.

Conclusion: What a Well-Prepared BOQ Delivers

A Bill of Quantities that’s accurately measured, clearly described and checked before tender changes how a project runs from that point on. 

For contractors, it means pricing a defined scope with confidence, then carrying that same pricing basis through delivery — payment applications and variations get valued against rates already agreed at tender, without renegotiating the basics on every package. For real estate developers and owners, it means a budget built line by line from measured quantities, with the same document tracking cost through construction and into handover. For everyone involved, disputes over scope get settled against a written record every party already agreed to. 

All of this depends on the BOQ itself: accurate, complete and checked before it reaches tender.

Learn more about Bauwise construction cost management software — explore how Associated British Ports advances cost management and risk management across its infrastructure projects, how SRC gains flexible project budget monitoring across €110 Million portfolio of over 850 projects, and other case study.

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