What is a bill of quantities in construction?

What is the purpose of a bill of quantities?

The bill of quantities, often abbreviated as BOQ, breaks down the scope of a project into clear, manageable items. This prevents contractors from having to guess requirements from plans and long blocks of text. Clients receive bids based on a comparable structure, and companies can systematically calculate quantities, units, and prices.

A BOQ should be clear enough that all parties have the same understanding of the work required. Unclear items cannot be improved by neat numbering—the decisive factors remain understandable content and complete project information.

Typical components

 
• Project and document details
 
• Chapters, sections, and item numbers
 
• Preliminary remarks and execution conditions
 
• Description of individual work items
 
• Quantity and unit, for example m², m, pieces, or hours
 
• Variables and project-specific additions
 
• Unit price and item total in the bid
 
• Compilations, discounts, surcharges, and other terms

Bill of quantities according to NPK

In Switzerland, bills of quantities are frequently structured using items from the Standardized Construction Catalog (NPK) . The NPK provides standardized service descriptions and their structure. The specific bill of quantities selects the items required for the construction project from this catalog and supplements them with quantities and project-specific details.

Services that are not appropriately covered in the catalog can be added as designated individual sections or as clearly labeled custom text. It is important to keep standard and individual texts clearly distinguishable for the reader.

From bill of quantities to quote

 
1. Check the bill of quantities for completeness and the correct version.
 
2. Understand items, quantities, units, and variables.
 
3. Calculate materials, labor, machinery, external services, and risks.
 
4. Apply unit prices and terms.
 
5. Document any ambiguities, assumptions, and variants transparently.
 
6. Review the quote and submit it in the required format.

What happens during execution?

After the contract is awarded, the structure for the project, work preparation, and quantity surveying can be reused. If the scope of work changes, the deviation should not simply disappear into an existing line item. Depending on the situation, a supplementary quote is created or the additional work is documented as time and material.

Common problems

 
• Quantities do not match the plan status or execution area.
 
• Variables were not fully selected.
 
• Preliminary remarks are overlooked during calculation.
 
• Custom text does not clearly describe inclusions and exclusions.
 
• Multiple file versions lead to quotes based on different statuses.

Digitally processing bills of quantities

In a digital process, line items, calculations, quotes, and subsequent quantities remain linked. Structured files do not need to be recreated in spreadsheets. With the quote functions from Caturix NPK-based and custom-built quotes can be created and carried forward with the project.

Frequently asked questions about bills of quantities

Is a tender document the same as a bill of quantities?

In Swiss construction practice, the term "Devis" is often used for a tender document or bill of quantities. Depending on the company, the term may also refer to the entire tendering process. The decisive factor is the specific content of the document.

What is the difference between a bill of quantities and a quote?

The bill of quantities describes the requested services. In the quote, the provider adds prices, terms and conditions, assumptions, and, if applicable, variants or exclusions.

Can a bill of quantities contain custom text?

Yes. Individual services and additions are possible. In NPK-based documents, they should appear in the designated sections and be clearly separated from standardized text.

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