If you are new to quantity surveying or construction, few terms come up more frequently than Bill of Quantities — and few documents have more practical importance to how a project is priced, tendered and managed. Yet for beginners, it can feel abstract. What actually is a Bill of Quantities? Who writes it? Who prices it? And what does it look like?
This guide answers all of those questions from the beginning. No assumed knowledge. No jargon without explanation. By the end, you will understand what a Bill of Quantities is, why it exists, what the different sections contain, how quantity surveyors prepare one, and how it is used throughout a construction project — from tendering through to the final account.
The Bill of Quantities — usually shortened to BOQ or BoQ — is one of the foundational documents in UK construction. Understanding it is essential whether you are studying for your RICS APC, working as a junior quantity surveyor, or simply trying to understand how the construction industry prices its work.
What Is a Bill of Quantities?
A Bill of Quantities is a document that lists every item of work required to complete a construction project, measured and described in a standard way, with quantities for each item and space for a contractor to enter their unit price.
Think of a BOQ like a shopping list — but for an entire building. Each item describes a piece of work: how it should be done, what materials to use, and how much is needed. Contractors fill in the price for each item. Add it all up, and you have the total cost of the project.
A quantity surveyor typically produces a BOQ during the design stage of a project. It is then sent to contractors as part of the tender package. Each contractor prices the BOQ independently, and the client uses the completed BOQs to compare tenders and select the contractor who offers the best value.
The BOQ is also used throughout the project to manage variations, value interim payment applications, and settle the final account at the end of the contract. It is one of the most important commercial documents on any traditionally procured construction project.
Why Does a Bill of Quantities Exist?
Before BOQs were used, each contractor tendering for a project had to measure the quantities of work themselves from drawings. This was time-consuming, expensive, and led to inconsistency — each contractor might measure differently, making tenders almost impossible to compare fairly.
The Bill of Quantities solves this problem. The client's quantity surveyor measures the work once, carefully and accurately, in a standard format. Every tendering contractor receives the same measured quantities. They simply insert their rates. This creates a level playing field for competitive tendering and saves contractors enormous amounts of time and cost in the bidding process.
- Consistency: Every contractor prices the same quantities, so tenders are directly comparable
- Accuracy: A skilled quantity surveyor measures the work precisely, reducing pricing errors
- Efficiency: Contractors only need to insert rates — not re-measure the entire project
- Transparency: The client can see exactly how each contractor has priced each element
- Contract management: The BOQ becomes part of the contract, used for variations and payments throughout the project
As Planyard explains, a well-structured BOQ 'fosters consistency and makes the comparison of tenders more straightforward'. It is the foundation of fair, competitive, transparent procurement in traditional construction.
What Goes Into a Bill of Quantities?
A Bill of Quantities is not a single list — it is a structured document divided into sections that mirror the physical construction sequence. Each section covers a different part of the building or a different category of work.
BOQ Structure
Typical Sections of a Bill of Quantities
| Section | What It Contains | Who Prices It |
|---|---|---|
| Preliminaries | Site setup, welfare, temporary works, project management, health and safety, insurance, plant, scaffolding | Main contractor |
| Substructure | Excavation, foundations, ground floor slab, drainage below ground | Groundworks contractor / main contractor |
| Superstructure | Frame, upper floors, roof, stairs, external walls, windows and doors, internal walls | Structural contractor / main contractor |
| Internal Finishes | Wall, floor and ceiling finishes throughout all rooms and spaces | Finishing trades / main contractor |
| Fittings & Furnishings | Fitted joinery, sanitary fittings, ironmongery, specialist equipment | Joinery / specialist |
| Services (Mechanical) | Heating, ventilation, air conditioning, plumbing, hot and cold water | M&E contractor |
| Services (Electrical) | Power, lighting, data, fire alarms, security, access control | Electrical contractor |
| External Works | Hard and soft landscaping, car parking, drainage, boundary treatments | Groundworks / landscape contractor |
| Provisional Sums | Allowances for work not yet fully defined at tender — to be confirmed later | Agreed between client and contractor |
Sections mirror the NRM2 elemental structure. Not every project includes all sections — a fit-out project may have no substructure section; a civil engineering project would use CESMM4 instead of NRM2.
Each of these sections contains individual line items — specific measured work items. A line item is the smallest unit in a BOQ. It describes one specific piece of work, states the unit of measurement, gives the measured quantity, and leaves space for the contractor to insert a rate and calculate the total.
What Does a BOQ Line Item Look Like?
Every line item in a BOQ follows the same basic format:
- Item reference — a code that identifies the item within the document (e.g. A.1.1)
- Description — a precise written description of the work, including specification requirements
- Unit — the unit of measurement (m², m³, m (linear), nr (number), item, tonne, etc.)
- Quantity — the measured amount, calculated from the drawings
- Rate — left blank for the contractor to complete at tender
- Total — Rate × Quantity, calculated once the contractor has inserted their rate
BOQ Example
Simplified BOQ Line Items — Substructure Section
| Item Ref | Description | Unit | Qty | Rate | Total |
|---|---|---|---|---|---|
| A.1.1 | Excavate to reduce levels, maximum depth not exceeding 0.25m, disposal off site | m³ | 245.00 | £18.50 | £4,532.50 |
| A.1.2 | Excavate foundation trenches, width not exceeding 0.30m, maximum depth not exceeding 1.00m | m³ | 38.40 | £28.00 | £1,075.20 |
| A.1.3 | Hardcore bed, 150mm thick, compacted, blinded with sand | m² | 186.00 | £12.40 | £2,306.40 |
| A.1.4 | In-situ concrete (C25/30), strip foundations, poured against faces of excavation | m³ | 22.80 | £165.00 | £3,762.00 |
| A.1.5 | Damp proof membrane, 1200 gauge polythene, lapped 300mm at joints | m² | 186.00 | £3.20 | £595.20 |
| Substructure Section Total (carried to summary) | £12,271.30 |
Illustrative example only — not a real project. Line items are measured and described in accordance with NRM2. Unit rates are inserted by the contractor at tender. The total for each section is carried to the summary page to build the full project cost.
The descriptions must be precise and unambiguous. If a description is vague or incomplete, contractors will interpret it differently and price it differently — defeating the purpose of the BOQ. Good description writing is a core skill for quantity surveyors preparing BOQs.
What Are Units of Measurement?
Different types of work are measured in different units, depending on the nature of the item. Understanding units is fundamental to reading and preparing a BOQ.
- m² (square metres): Used for flat surfaces — floor finishes, roof coverings, wall cladding, plasterwork, tiling
- m³ (cubic metres): Used for volumes — concrete, excavation, fill material, hardcore
- m (linear metres): Used for items measured by length — pipework, gutters, kerbs, skirting boards, railings
- nr (number): Used for countable items — doors, windows, light fittings, manholes, handrails
- kg or tonne: Used for reinforcing steel, structural steelwork, and other weight-based materials
- item: Used for work that cannot easily be measured in other units — a lump sum for a specific piece of specialist work
Getting the unit right is critical. Pricing concrete in m² instead of m³, or pipework in m² instead of m, gives completely wrong quantities. A junior QS should always sense-check: does this unit logically match how this work would be done in practice?
What Is NRM2 and Why Does It Matter?
In the UK, Bills of Quantities are prepared following a standard method of measurement. Without a common standard, different QSs would describe and measure the same work differently, making BOQs impossible to compare or use reliably.
The current standard for building works is NRM2 — the RICS New Rules of Measurement: Detailed Measurement for Building Works, published by the Royal Institution of Chartered Surveyors (RICS). NRM2 was introduced in April 2012 and became operative on 1 January 2013, replacing the previous Standard Method of Measurement 7th Edition (SMM7).
NRM2 sets out how every type of building work should be: described (what the description must include), measured (which unit to use and how to calculate quantities), and organised (which section of the BOQ it belongs in).
For civil engineering works — roads, bridges, drainage, utilities — the equivalent standard is CESMM4 (Civil Engineering Standard Method of Measurement, 4th edition), published by the Institution of Civil Engineers (ICE).
Using a recognised standard ensures that a BOQ produced by one QS is understood and priceable by any contractor anywhere in the UK. It is the common language of construction pricing. As Metroun explains, NRM2 'deals with Bill of Quantities — all aspects of them' and governs how items are listed, described and quantified for pricing.
How Is a BOQ Prepared? The Process
Step 1: Study the Drawings and Specifications
The quantity surveyor starts with the design drawings (architectural, structural, M&E) and the project specification. The specification describes the quality and standard required for each element — what grade of concrete, which type of brickwork, what specification of window system. This forms the basis of the item descriptions.
Step 2: Taking Off (Quantity Take-Off)
Taking off is the process of reading the drawings and calculating the quantities of each item of work. A QS measures every element systematically: area of brickwork, volume of concrete, linear metres of drainage, number of windows, and so on. This was traditionally done on paper dimension sheets; today, it is usually done using digital take-off software such as Bluebeam, CostX or PlanSwift, or directly from BIM models.
Taking off requires careful attention to the rules in NRM2: which items must be measured separately, what deductions must be made for openings, and how different types of the same work should be distinguished.
Step 3: Abstracting and Billing
Once quantities are taken off, they are organised into the BOQ structure — grouped into the correct sections (substructure, superstructure, services, etc.) and ordered logically. Each item is given a description that complies with NRM2 requirements: the description must be clear enough for a contractor to price it without referring back to the QS.
Step 4: Adding Preliminaries and Provisional Sums
The Preliminaries section is the first section of most BOQs. It covers the contractor's general site costs — setting up and running the site, temporary works, welfare facilities, project management, health and safety, insurance and other items not directly part of the measured building work. Contractors often price preliminaries as a significant proportion of their total bid — sometimes 10-15% of the construction cost on a complex project.
Provisional Sums are allowances included in the BOQ for work that has not yet been fully designed or specified at tender stage. They are not firm prices — they are placeholders that will be replaced by actual costs once the scope is confirmed. NRM2 distinguishes between Defined Provisional Sums (where the contractor can plan around them) and Undefined Provisional Sums (where they cannot).
Step 5: Issuing for Tender
The completed BOQ — with quantities and descriptions but no rates — is included in the tender package issued to contractors. Contractors complete the tender by inserting their rates for each item, calculating totals, and returning the priced BOQ as part of their bid. The client and QS then analyse the returned tenders, checking rates are reasonable, identifying any pricing anomalies, and recommending a contractor.
How the BOQ Is Used During the Project
The Bill of Quantities does not just serve the tender. Once the contract is awarded, it becomes a live commercial document used throughout the project.
Variations
When the scope of work changes after the contract is signed — a design change, an omission, an addition — the change is valued using the BOQ rates. If the contractor has priced brickwork at £85/m² in the BOQ, that rate is used to value additional brickwork ordered as a variation. This is why BOQ rates need to be fair and market-reflective — they will be used for years after tender.
Interim Valuations and Payments
Each month, the quantity surveyor values the work completed on site. On a BOQ contract, this involves assessing what percentage of each BOQ item has been completed and calculating the value. The result feeds into the interim payment application submitted to the client for payment.
Final Account
At the end of the project, the QS prepares the final account — the total reconciliation of everything the contractor is owed. The BOQ forms the starting point: contract sum, plus variations, plus adjustments for provisional sums, minus omissions. The final account can only be settled accurately if the BOQ has been well prepared and maintained throughout the project.
BOQ vs Schedule of Rates — What's the Difference?
A Schedule of Rates is similar to a BOQ but without the measured quantities. Instead of fixed quantities for each item, the schedule just lists work items and the contractor's agreed rate. The actual quantities are measured as work is done during the project.
Schedules of rates are used where the full scope of work cannot be defined upfront — for example, maintenance frameworks, term contracts, or early-stage enabling works. They give the client agreed pricing without locking in quantities.
A BOQ has fixed quantities measured from the design drawings. A schedule of rates has no fixed quantities — just agreed unit rates to be applied to measured work. Both documents use the same line item format; the difference is whether quantities are filled in at tender.
Does Every Project Have a Bill of Quantities?
No. The BOQ is most commonly used in traditional procurement — where the design is substantially complete before tendering, and a quantity surveyor can measure accurate quantities from completed drawings.
Under design and build procurement — which has become increasingly common in the UK — the contractor takes on design responsibility. The employer's QS may produce an Employer's Requirements document or a high-level schedule of works instead of a full BOQ. Without a BOQ, contract sums are agreed on a lump-sum basis, and the contractor takes more risk on scope and quantities.
On smaller projects, a simplified BOQ or schedule of works may be prepared — less formally structured than a full NRM2 BOQ but still providing the same basic function of describing and quantifying the work for pricing.
Frequently Asked Questions
What does BOQ stand for?
BOQ stands for Bill of Quantities. You may also see it written as BoQ. Both mean the same thing: a measured document listing all items of construction work with quantities and space for rates, used for tendering and contract management.
Who prepares a Bill of Quantities?
A Bill of Quantities is prepared by a quantity surveyor (QS), typically working for the client's cost consultancy or PQS firm. The QS measures quantities from the design drawings and specification, following the rules in NRM2 (or CESMM4 for civil works), and produces the structured document sent to contractors at tender.
What is taking off in construction?
Taking off (or quantity take-off) is the process of reading design drawings and calculating the quantities of each item of work — how many square metres of brickwork, how many cubic metres of concrete, how many linear metres of drainage pipe. It is the core measurement skill of a quantity surveyor and the foundation of BOQ preparation.
What is the difference between NRM1 and NRM2?
NRM1 governs cost planning — producing elemental cost plans at early design stages when full drawings are not yet available. NRM2 governs detailed measurement — producing Bills of Quantities from completed design drawings for tendering. NRM1 is used earlier in the project; NRM2 is used at tender stage. Both are published by RICS.
What is a Provisional Sum in a BOQ?
A Provisional Sum is an allowance included in the BOQ for work that has not been fully designed or specified at tender stage. It is a placeholder, not a firm price. Once the scope is confirmed, the Provisional Sum is replaced by actual measured and priced work. NRM2 distinguishes between Defined Provisional Sums (contractor can programme for them) and Undefined Provisional Sums (contractor cannot programme for them at tender).
Is a BOQ legally binding?
Once incorporated into a signed construction contract, the priced BOQ is a contract document — it forms part of the legal agreement between the client and contractor. The rates in the BOQ are binding for valuing variations and measuring work. Under JCT contracts, the BOQ is one of the core contract documents and takes a defined place in the hierarchy of contract documents.
Can you have a BOQ on a design and build contract?
Rarely in the traditional sense. Under design and build, the contractor carries design risk, and the scope may not be fully defined at tender. Clients may issue an Employer's Requirements document or a pricing schedule instead. Some design and build projects include an indicative BOQ as a pricing tool, but it does not have the same contractual status as a BOQ in a traditional procurement route.
