Engineering blog
20 Oct 2021

What AEC Companies Need to Know About the Bill of Quantities

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If you work in the AEC industry, you need to be up close and personal with the definition and relevance of the bill of quantities.

Whenever you embark on a project, you must ensure a full and accurate documentation, whether for construction estimation, real estate estimation or anything else.

In today’s article, we’ll give you the foundation of what you need to know.

Introduction: What is a Bill of Quantities?

A bill of quantities (commonly referred to as “BOQ” or even “BQ”) is a document that itemizes labor, materials, parts and their costs. It is prepared by a cost consultant (typically a quantity surveyor) and issued to tenderers so they can determine a price.

Since all tendering contractors price the same quantities, the bill also lays out an accurate and fair system for tendering.

‘Quantities’ or ‘quantity’ in this context means the calculated or “measured” amounts that are included in the BOQ. They may be measured in area, volume, number, length, time or weight.

Developing the bill of quantities demands that the design has been completed and that a specification has been made. Specifications refer to the materials, work, and products required by the construction contract, and exclude quantity, cost and drawn information.

Furthermore, it is crucial that the BOQ is developed to a standard methodology that is recognized by everyone involved in the construction project. This is to avoid ambiguities or misunderstandings.

For example, until recently in the UK, BOQs for general construction work were usually prepared according to the 7th edition of the Standard Method of Measurement. (It was replaced in 2013 by the New Rules of Measurement.)

How is a Bill of Quantities Prepared? What are its Major Parts?

Generally, an experienced estimator or quantity surveyor will use specialized software to measure the different aspects of the construction plan. Once this is completed, labor and material items are compiled. The BOQ will also cover costs for unexpected cost exceeds.

The major parts of a BOQ in construction is as follows:

  • Form of Tender

  • Information

  • Requirements

  • Pricing Schedule

  • Provisional Sums

  • Day Works

There are two main types of BOQs:

  • Bill of Labor

  • Bill of Materials

Why is the BOQ Important?

The bill of quantities is one of the most important documents in construction. Here are a few reasons why.

  • Comparison and Evaluation Opportunity: Since the details of all the items are described, evaluation can be thorough. Furthermore, it helps compare each contractor based on the items so a fair deal can be made.

  • Detecting Future Problems: The level of detail means that it is possible to detect potential future issues and plan ahead to eliminate or mitigate them.

  • Better Project Planning: Because items and their quantities are listed, the project planner only has to set the duration of work and arrange the resources.

  • Limits Timeframe: We can arrange the materials on time since we know their quantities.

  • Transparency: Chances of corrupt practice are reduced due to the details of the items given.

  • Reduction of Costs: Since the bill helps to reduce the timeframe, it automatically also helps to reduce the costs.

Difference Between BOQ and BOM

Both the BOQ and bill of materials (BOM) go hand in hand and are crucial to project planning. They aid contractors and project planners in understanding inventory requirements of a project.

While the BOQ lists the number of materials, the BOM concerns the list of inventory, such as parts, components, raw materials, instructions, and so on. It provides clarity on what is required for completion of the project.

Typically a BOM will appear in hierarchical format. The highest level will show the finished product, while the lowest level will display individual materials and components.

A bill of materials can display information in one of two ways: an implosion display or an explosion display. The implosion shows the linkage of individual parts to assemblies. Conversely, the explosion displays an assembly broken down into individual parts.

As an example, a computer may be exploded into processors, computer chips, hard drive, and RAM panels. A processor would be further exploded into a register, control unit and arithmetic unit.

On the other hand, requirements for the control unit, register and arithmetic unit can be imploded into the requirements of the processor, which are further imploded into the requirements of the computer.

Common Mistakes in BOQs

An ideal BOQ will be accurate and comprehensive. There are, however, some common mistakes you should watch out for:

  • Inaccurate measurement of the quantities

  • Insufficient information in descriptions

  • Inclusion of irrelevant preliminary items

  • Discrepancies between the BOQ and the specifications or drawings

  • Omissions

  • Double counting of items (can occur due to more than one surveyor working on the same BOQ)


Regardless of the type of contract, at some stage in your project’s procurement process, the works shall have to be quantified.

An accurate BOQ makes your process far easier and reduces reliance on guesswork. However, the BOQ is only one of the essential contract documents required for construction projects, and aside from contract documents, you also require construction documentation.

Luckily for you, BluEntCAD is just a click away. We automate, streamline and organize the construction documentation process for homebuilders, real estate developers, large engineering and architectural companies, and home designers for large to medium-sized hospitality, commercial, infrastructure and residential projects.

Ready to take your building project to the next level with construction documentation services? Contact us now!

Maximum Value. Achieved.



Your Citation

CAD Evangelist. "What AEC Companies Need to Know About the Bill of Quantities" CAD Evangelist, Oct. 20, 2021,

CAD Evangelist. (2021, October 20). What AEC Companies Need to Know About the Bill of Quantities. Retrieved from

CAD Evangelist. "What AEC Companies Need to Know About the Bill of Quantities" CAD Evangelist (accessed October 20, 2021 ).

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