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How to Calculate a Bill of Quantities

A bill of quantities (BoQ or BQ) is a document that itemizes the materials, labor and costs required to complete a construction project. It’s most commonly used on larger projects and helps contractors to estimate the work they will need to do.

It’s prepared according to a standard methodology and is developed after the design has been completed and a specification made. This makes it easier to avoid ambiguities and misunderstandings, which can lead to disputes.

Units of Measurement

A bill of quantities is a document that is used to estimate the cost of construction work. It includes a list of all the materials and components that are required for a project, along with their description, unit of measure, and cost estimate. This helps contractors price the work and ensures that they complete the project within budget.

A bill of quantity is typically prepared by a cost consultant (usually a quantity surveyor) that provides project-specific measured quantities of the items identified in drawings and specifications for a built asset such as a building. A bill of quantities is a valuable costing tool and should be prepared as soon as possible after the design stage and prior to tendering.

There are different estimating approaches that can be used to prepare a bill of quantities. One of the most common is the unit rate estimating approach. This uses predetermined labour output rates and plant output rates to calculate the cost per unit of the measured works.

Using these rates can help an estimator to come up with a realistic costing that can be relied on to price the bill of quantities for bidding purposes. However, these rates are generally based on past research and may not reflect the current market.

Some estimates use a cost plan method that combines the unit rate estimating approach with a value-based approach to arrive at the final cost of the work. This method uses the value of the work, along with an expected level of risk and other factors, to determine the cost of the work.

This approach is particularly effective on complex projects, where it can reduce uncertainty and provide greater price certainty during the tendering process. The cost plan method can also be applied to small scale projects, where it can help control costs and improve productivity by avoiding unnecessary work.

An approximate bill of quantities is also sometimes prepared on a project where a firm bill of quantities cannot be prepared until after the tendering stage has occurred. Approximate bills are usually included in the tender documents as a guide with a caveat that responsibility for measuring quantities lies with the supplier and the drawings and specification take priority over any description in the approximate bill.

Item Numbers

A bill of quantities is a great way to document the work involved in the construction of a building. It allows you to keep track of the costs and compare them against the estimates provided by your subcontractors.

To create a good bill of quantities, you must first determine the materials and products you need to complete your project. You can do this by looking at the plans and specifications that your architect has prepared for you. Once you have an idea of what you need, write down the name of each product and its quantity in your spreadsheet.

Next, you need to decide what unit of measurement to use for each item. For example, if you have concrete on your list, you might choose cubic meters as your unit of measurement.

The key is to remember that a bill of quantities must be concise and clear. This means that only the pertinent information should be included in each line item, and that the information must be arranged into relevant groups or categories.

One of the best ways to do this is with a spreadsheet. Make sure you include a column for each item number, as well as a column for the specification or description, the unit of measurement and finally, the amount, rate and cost.


A bill of quantities is a document used in the construction industry that itemizes materials, parts, and labor (and their prices) required for a project. This enables contractors to price the work for which they are bidding, and it is often the first step in a contract.

A BoQ should be prepared by a quantity surveyor, usually at the engineering firm responsible for the design of the project. This ensures that the scope of work and quantities are determined by a neutral party, and that bidding contractors compete under fair conditions.

The first step in preparing a bill of quantities is to define the scope of the project. This includes defining the extent of the building or site and the specific requirements of the project. It also includes obtaining the necessary documents, such as architectural drawings and structural drawings, to help you determine the quantities of materials, labor, and equipment needed for the project.

Next, you should break the work into smaller items, such as individual rooms or sections of a building. This helps you estimate the amount of materials and services that are needed for each section or room, and it allows you to prepare a detailed BoQ that is easy to understand.

Another way to break down the work into items is by preparing a schedule of work. This is an instructional list that describes the significant work and materials that will need to be completed. It can help the contractor estimate the quantities of those items and the number of hours it will take to complete the work.

Finally, you should determine how to measure the items in your BoQ. This can be done by taking off the items from drawings and schedules of work or by using a standard method of measurement, such as a tape measure or calipers.

You can use a standard Bill of Quantities Template to calculate the quantities that are needed for a project, but it is important to remember that the template is not always accurate. It is a good idea to check the numbers before sending the template to potential suppliers, so that you can be sure the numbers are correct.


Bill of quantities are documents used in the construction industry that list labor, materials and parts required for a project. They are prepared by a cost consultant (usually a quantity surveyor) and issued to tenderers so they can determine a price for the work.

The bill is a vital document in the construction industry as it allows for accurate bids and provides a means to compare bids from different contractors. It also helps to prevent disputes between contractors and ensures that all parties are aware of the work that needs to be done on a project.

It is important to ensure that a bill of quantities is developed according to a standard methodology and is compatible with all other documentation that may be relevant to the construction contract such as drawings, specifications and other tender documents. This is so that any misunderstandings or discrepancies can be resolved and the costs associated with these can be avoided.

A bill of quantities is often prepared by a quantity surveyor or cost consultant during the pre-construction phase of a construction project. They will take the measurements from the design team’s drawings and specifications and produce a detailed estimate of all the materials and labour required for a construction project.

They will prepare a bill of quantities in accordance with a standard method of measurement and issue it to tenderers for them to prepare a price for the work. This is so that all tendering contractors will be pricing the same quantities and so a fair system can be established for tendering.

The document is broken down into sections that reflect each element of the construction works, such as earthworks, concrete, masonry and steelwork. It is a popular structure for measured works and is also the one we use in our bill of quantities template.

Once the bill has been prepared, it can be printed out for use by contractors and other relevant parties during a construction project. It can be revised and updated as the project progresses and is useful for creating payment applications during the construction process.