Bill of Quantities(BoQ): A Complete Breakdown

17th January 2024

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What is a bill of quantities, and why are they critical to the success of major construction programmes? Discover everything from the origins of the BoQ, to best practices for preparing them in this comprehensive guide. 

Construction as a business sector stands as a cornerstone of economic growth and societal development worldwide. Not only does it drive economic prosperity by fostering innovation and investment, but it also meets the fundamental needs of modern civilisation, from housing and transportation to healthcare and education.

In the dynamic world of construction, planning and precision are extremely important. The whole construction project depends on how accurate your cost and time estimations are. Imagine having a blueprint, not for the physical structure itself, but for all the components that come together to create it. This comprehensive guide unveils the hidden language of construction—a language that speaks volumes in numbers, measurements, and meticulous details. It’s a language known as bills of quantities or simply put, BoQ.


1. What are bills of quantities?

A bill of quantities, or BoQ or simply BQ, is like a detailed shopping list for a construction project. Imagine you’re building a house and you need to know exactly how much of each material such as bricks, cement, and wood you will need. The BoQ does just that. It lists how much of each item is required for the project.

A bill of quantities is put together by a construction professional called a quantity surveyor. To create it, they need to know exactly what the building will look like and what materials will be used. Bills of quantities are mostly used for big construction projects. In the case of smaller projects or renovations, you might not need a BoQ.

The origins of bills of quantities can be traced back to the late 18th and 19th centuries when the UK construction landscape was rapidly changing with the onset of the Industrial Revolution. At that time, architects and builders began to recognise the need for a standardised method of quantifying construction materials and labour. In the 20th century, with the construction industry’s continued growth and complexity, the advent of modern computing and software further streamlined the preparation and management of bills of quantities, making them even more indispensable for large-scale construction projects.


2. What are bills of quantities used for?

Bills of quantities form an integral component of the tender package provided to potential suppliers to solicit pricing. Here’s a detailed breakdown of their critical functions:


Standardising the tendering process

  • BoQs standardise the tendering process, allowing contractors to prepare precise cost estimates based on the same information.
  • This fosters fairness and transparency in the tendering process.


Facilitating tender analysis

  • BoQs enable thorough tender analysis, where both total project costs and individual rates can be evaluated.
  • This ensures that contractors submit complete, compliant bids that align with specifications and meet budgetary goals.


Cost control and projections

  • BoQs provide detailed schedules and breakdowns, offering owners visibility into cash flow needs over various project cycles.
  • This helps in predicting and managing project expenditures effectively.


Foundation for contracts

  • BoQs act as the foundation for the final contract between the client and the contractor. In case of disputes or claims during construction, they provide a reference point for conflict resolution.


Transparency and error reduction

  • By specifying materials and labor, BoQs create transparency around scope and pricing, reducing errors and misunderstandings.
  • This ensures that all parties have a clear understanding of the project’s requirements.


Maintenance and future expansion

  • The comprehensive information within a BoQ becomes an invaluable record for future maintenance, repairs, and potential expansions.
  • This saves time and effort compared to re-quantifying for subsequent work on the project.


In summary, BOQs play a crucial role in making the tendering process more uniform, pricing more precise, and project costs more predictable. They serve as a cornerstone document, not only during the construction phase but also for the long-term management and development of projects.


3. What does a bill of quantities include?

By now, we all have understood the significance of bills of quantities in construction projects as they provide us with accurate quantities of items, materials, and labour required for the completion of the project. While the format may vary, several essential components are typically found in a comprehensive BoQ:


Project information

  • It includes project details like the project name, owner, location, and the BoQ’s date of creation. This context is essential for clarity and record-keeping.



  • Each entry in the BoQ is assigned a unique item number to simplify referencing, especially in extensive lists.


Item differentiation

  • Items are categorised as materials or labour, providing a clear distinction for measurement and pricing purposes.


Detailed descriptions

  • The BoQ often includes brief but precise descriptions for each item. For instance, if the list includes ‘paint,’ it might specify whether it is ‘interior’ or ‘exterior’ paint to avoid ambiguity.


Unit of measurement

  • The unit of measurement varies based on whether it is a material or labour unit. Materials are typically measured in counts such as gallons, cubic, square, linear metres, tons, etc. whereas labor is measured in time units, such as hours or per installation, depending on the specific task.



  • The BoQ specifies the quantity of each material or the time required for each labour item. This quantification is fundamental to understanding the scope of the project.


Unit costs

  • It indicates the prices for materials and hourly rates or fees for labour. These unit costs are pivotal in calculating the total costs.


Total item cost

  • For each entry, the BoQ calculates the total cost by multiplying the unit price by its quantity. To arrive at the overall budget, we sum up the costs of these individual items.


Terms and conditions (optional)

  • Some BoQs include terms and conditions related to the project, such as warranties, payment terms, and other contractual details.


A well-structured BoQ with itemised lists, clear descriptions, and comprehensive cost calculations provide a financial overview for construction projects. It not only guides procurement and scheduling but also serves as a vital tool for cost and commercial management.


4. How to prepare bills of quantities?

Before we get into the step-by-step method of drafting a bill of quantities, it’s imperative that we learn about the different types of bills of quantities or we would rather term them as different stages for a bill of quantities.

  • Preliminary Bill of Quantities (PBQ) – This bill estimates the initial project costs, covering concepts like site preparation and early-stage construction activities.


  • Approximate Bill of Quantities (ABQ) – An approximate bill of quantities (ABQ) provides cost estimates for different construction phases, helping with budgeting and financing.


  • Revised Bill of Quantities (RBQ) – RBQs are updated versions of the original BoQ, reflecting changes in the project scope or design.


  • Firm Bill of Quantities (FBQ) – A firm bill of quantities (FBQ) is a finalised and agreed-upon version of the BoQ, used for tendering and contract execution.


  • Provisional Bill of Quantities (PBQ) – Provisional Bill of Quantities (PBQ) includes items with uncertain quantities or costs, often used when exact figures are hard to determine during project planning.


  • Contractor’s Bill of Quantities (CBQ) – The contractor prepares CBQs, detailing their specific requirements and pricing for a project, often in response to an FBQ.


These different types of bills of quantities explain the progress of the bill and what clients and contractors should expect at what stage. According to the BoQ type, some steps in the creation process might vary but the whole idea is pretty much the same.


5. Step-by-step guide for creating bills of quantities


1. Initial project documentation

Begin by collecting all relevant project documents, including architectural plans, engineering drawings, and specifications. These documents set the foundation for your BoQ.

2. Itemisation and categorisation

Review the project documents thoroughly and itemise all materials and labour required.
Categorise items as either materials or labour and provide concise, yet detailed descriptions for clarity.

3. Quantify with costs

Based on the project specifications, start with quantifying all the items required in the projects and their associated costs. Calculate the total costs involved. This will also help you calculate the total man hours required to complete the project.

4. Quality control

Review and cross-check your BoQ thoroughly to ensure accuracy and consistency. This is a crucial step to avoid any errors. It’s best practice to get more eyes to review your bill of quantities, leaving zero space for any discrepancies.

5. Compliance and standards

Ensure that your Bill of Quantities adheres to the relevant standards and guidelines in the UK, such as the New Rules of Measurement (NRM) or any specific industry standards applicable to your project.

6. Final compilation

Organise your BoQ in a clear and easily understandable format. Include a cover page with project details and any terms and conditions if required.


6. Tips for accuracy and best practices

  • Keep abreast of industry changes, regulations, and market rates in the market you are working in. Regularly update your BoQs to reflect current conditions.


  • Maintain consistent terminology and item descriptions throughout the BoQ to avoid confusion. Refrain from adding vague variances while doing measurements. Do it accurately by referring to the drawing section and details.


  • Consider utilising specialised software for BoQ preparation like CostX, which can enhance accuracy and efficiency. Ensure to write detailed descriptions with available specifications and details.


  • Engage with architects, engineers, and contractors to ensure alignment between the BoQ and the project’s technical specifications.



Creating a bill of quantities is an essential skill for construction professionals in the UK. By following this step-by-step guide and adhering to best practices, you will equip yourself to prepare accurate and reliable Bills of Quantities (BoQs) for your construction projects.


7. Bills of quantities as a Soben service

At Soben, we take pride in our role as a global construction consultancy, and one of our core services is providing accurate Bills of Quantities (BoQs) to our valued clients and contractors. With a commitment to precision and professionalism, Soben has established itself as an industry expert in delivering comprehensive BoQs. Our team of experienced professionals brings a wealth of knowledge and expertise to the table, ensuring that our clients receive BoQs that are not only accurate but also aligned with industry standards and regulations.

While our focus is on accuracy, we approach this service with a client-centric mindset, understanding the unique needs and specifications of each project. Through our BoQ services, we aim to facilitate cost-effective project management and procurement, ultimately contributing to the success of your construction endeavours.