Bill of Quantities:
Detailed Cost Report

A Bill of Quantities is required when a client wants all potential contractors to price the same detailed scope of work. The BoQ itemises materials, labour, plant, and associated quantities so that bids can be fairly compared on a like-for-like basis, rather than each contractor measuring quantities from the drawings. This helps secure competitive, transparent pricing and supports fair evaluation.

A detailed Bill of Quantities is used when a project owner needs a reliable, itemised breakdown of all expected costs before awarding contracts. This includes every material and labour element with units, quantities and unit rates, providing a strong basis for cost planning, cash-flow forecasting and financial approvals. It ensures nothing essential is omitted from the budget.

For larger or technically complex builds (e.g., commercial developments, multi-structure sites, or specialised infrastructure), a detailed Bill of Quantities is required because the scope is too extensive for simple cost estimates. It helps break down work into detailed cost components, enabling project managers to control scope, pricing, and change management throughout the project lifecycle.

A Bill of Quantities is required when standardised measurement and costing are needed across clients, designers, quantity surveyors, and contractors. Using a Bill of Quantities eliminates ambiguity in unit descriptions and quantities, ensuring all parties price work from the same data and reducing disputes over scope interpretation.

A Bill of Quantities is also required during the construction phase to manage variations to the original scope, interim valuations and progress payments. Because the Bill of Quantities breaks down the entire project, it provides a benchmark against which actual work completed, changed items or additional costs can be measured and priced fairly.

While a Bill of Quantity contains a list of materials with a combined labour and materials rate or dollar value, a Bill of Materials is a list of each individual material item required in order to complete the whole project or process.

A skilled quantity surveyor or experienced estimator uses specialised computer software to measure various aspects of the construction plans. Once these are measured, material and labour items can be compiled, usually into sequenced folders, that relate to the total bill or estimate.

A Bill of Quantities provides:  

• A clear understanding of the scope of work involved in the project
• Assists all parties with interim payment evaluations
• Clarifies which items need to be procured at specific phases of the project
• Allows for accurate estimations of all project costs
• Assists with cash flow for the project

The time it takes to prepare a Bill of Quantities can vary depending on the size and complexity of the project. For a small to medium-sized project, it can take anywhere from a few days to a couple of weeks. For larger projects, it may take several weeks or a few months.

At Duo Tax, we strive to provide accurate and detailed BOQ reports in the most efficient time frame possible.

Yes, a Bill of Quantities can be revised if there are changes in the project, scope, design or if new information becomes available that affects the project costs.

Ideally, a Quantity Surveyor should be engaged once preliminary plans are sufficiently developed but before lodging the Development Application. Early engagement helps avoid delays, incorrect levies and requests for further information from council.