A Complete Guide to Bill of Quantities in the UK

A bill of quantities (BoQ) is a tender document, usually prepared by a quantity surveyor, that lists every item of work on a construction project with its measured quantity. Every contractor prices the same list, which keeps tendering transparent, and the priced BoQ then supports cost management, variations and interim valuations. In the UK, building work is measured to NRM2, part of the RICS New Rules of Measurement (checked October 2026).

What Does BoQ Mean?

BoQ is short for bill of quantities: the scope of the project broken into measured items. Each item has a description and a quantity, which may be a number, length, area, volume, weight or time depending on the work. Items sit in work sections that follow a standard method of measurement (NRM2 for building, CESMM for civil works), with a column for tenderers to insert their rates.

The QS issues the bill at tender stage, so contractors can price the works without measuring everything again from the drawings. Because they all price the same quantities, the tenders can be compared directly.

What Is Included in a Bill of Quantities?

1. Preliminaries
   The general conditions that apply across all work sections: site rules, health and safety requirements and contractual obligations.
2. Measured works
   Each element (substructure, superstructure, finishes, services) is measured and itemised to a standard method, NRM2 (New Rules of Measurement) for building or CESMM (Civil Engineering Standard Method of Measurement) for civils.
   • Substructure covers items such as excavation, foundations and damp-proof membranes.
   • Superstructure covers walls, roof structures, windows and so on.
3. Schedule of rates (if applicable)
   Some bills include a schedule of rates for pricing variations or additional work once the job is on site.
4. Contingency sums
   Money set aside for unforeseen costs. It can be a single lump sum, or it can cover a specific element whose extent isn’t clear at tender stage.
5. Provisional sums and provisional quantities
   Used where the details or quantities of some work can’t be measured at tender. They let the work be adjusted later without an immediate variation order.
6. Dayworks or prime cost items (if relevant)
   Prime cost (PC) items cover certain specialist services or works. Daywork rates cover trades paid by the hour, plus materials.

Contractors, subcontractors and the design team then work from the same document for the rest of the project.

"Without a proper system, you are essentially flying blind. You wouldn't know if there was a problem until it was too late, and you wouldn't truly know if you had made a profit until the project was already finished."

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Graham Eastwood Office Manager  ·  Karringtons Ltd  ·  Kent, United Kingdom

Bill of Quantities Example

Here is part of the substructure section of a BoQ for a small extension, with illustrative rates. The QS measures the quantities, and each tenderer fills in the rates.

Because every contractor prices the same 42 m³ of excavation, tenders can be compared line by line. If the trench turns out to need 50 m³, the extra 8 m³ is valued at the tendered £38.00 rate, so the variation is quick to agree.

BoQ vs. BOM (Bill of Materials): What’s the Difference?

A BoQ measures the works, including labour, plant, overheads and materials. It is a construction document used for tendering, costing and contract management, and it follows standard rules of measurement so tenders can be compared fairly.

A bill of materials (BOM) comes from manufacturing and product assembly. It lists the components or materials needed, often with no labour or installation method, and is set up for buying parts rather than split into work sections. Labour on those jobs is usually accounted for separately.

"Now, I can just go into my material budget and see exactly how much we've ordered across every purchase order in one single view."

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Grant Collins Quantity Surveyor  ·  Skyler Contracting  ·  Kent, United Kingdom

How to Calculate a Bill of Quantities

A quantity surveyor or cost consultant usually prepares the BoQ. In outline:

1. Get the design and specification ready
   • You need the architectural drawings, structural details and any specialist design.
   • The specification sets out materials, finishes and workmanship.
2. Take off quantities
   • Taking off means measuring from the drawings and specification.
   • Use standard units, such as m² for walls and m³ for concrete.
   • Splitting items by section or trade makes it easier to carve the work into subcontract packages.
3. Organise the bill
   • Group the measured items under the headings of your chosen method, usually NRM2: preliminaries, substructure, superstructure, services, finishes and so on.
   • Measure any civil engineering work to CESMM4.
4. Price the items
   • Rates come from historical cost data, supplier quotes or subcontractor prices.
   • Allow for overheads, profit and risks such as material price fluctuations.
5. Add contingencies and provisional sums
   • Look at where the design or site conditions are still uncertain.
   • Put in provisional sums for details that will be firmed up later.
6. Check and issue
   • Check the calculations for errors and omissions.
   • Make sure special requirements match the specification and drawings.
   • Issue the final bill with the tender documents.

Practical tips

• Measure to a standard method. It removes ambiguity and heads off contractual disputes later.
• Cross-check each measured item against the drawings and the specification.
• Construction software and BIM (Building Information Modelling) tools can produce a BoQ faster, but they don’t replace the QS’s judgement.
• If you can, talk to contractors or subcontractors early. Their input makes the estimate more accurate and can cut contingencies you don’t need.

Example Scenario: New Office Building

For a new three-storey office block, you would:

1. Go through the architectural and structural drawings.
2. Measure each element: foundations, columns, beams, floor slabs, walls, doors, windows, mechanical and electrical works.
3. Put each item in its work section: foundations in substructure, walls and columns in superstructure, flooring and painting in finishes.
4. Get quotes from suppliers and subcontractors to price the measured works.
5. Allow a contingency sum for unforeseen ground conditions or design changes.

Advantages of a Well-Prepared BoQ

Tenders are like for like, and the client gets a clearer view of the total cost and the contingencies. Once work starts, the rates in the bill are used to value changes and work out interim payments. Measuring to a standard method also leaves less room for argument.

Avoiding Common Pitfalls

1. Discrepancies. An item that is in the design but missing from the BoQ, or the other way round, leads to disputes. Check the bill against the drawings and specification before issuing it.
2. Thin contingencies. Skimping here leads to cost and time overruns later. Base the allowance on what you know about the project’s complexity.
3. Trusting the software. Automated tools get it wrong when the model or data behind them is wrong. Check their output yourself and apply what you know about the site.
4. Poor coordination. When the project team doesn’t talk, measurements conflict. Hold regular coordination meetings and keep everyone up to date on design changes.

Approximate Bills of Quantities

When parts of the design are incomplete, the QS may issue an approximate (or notional) bill of quantities. Its measurements are indicative, so expect more variations once the details are settled. If the actual quantities differ significantly, the contractor may be entitled to claim extra time or cost under the contract.

Managing a BoQ with Planyard

Developers, main contractors and subcontractors all work from BoQs, whether they prepare them, price them or administer the contract against them.

"When you look at your margin without using Planyard, you might think you’re making 21%. But are you really if things have been missed and you can’t see them? Planyard lets you see a true margin all the time."

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Lee Covington Owner  ·  E&N Group Ltd  ·  London, United Kingdom

Tracking a priced BoQ by hand through the job is slow and easy to get wrong. Planyard keeps it on a live budget:

• Upload your BoQ and costs are tracked against it automatically on a real-time budget.
• Link BoQ items to purchase orders, subcontracts and change orders.
• Approval workflows check that payments match the agreed quantities and rates, so nothing is overbilled.
• CVR and forecast reports run in one click and show cost variations as they happen.

Planyard is our product and works after the BoQ is priced; it does not do takeoff. For measurement and pricing tools that build the BoQ itself, see our guide to the best quantity surveying software.