A bill of quantities (BOQ) is the itemised list of the work in a construction contract: each item with a description, a unit of measurement, a quantity, and a rate. Multiply quantities by rates and you have the contract value, line by line. The BOQ is produced for the tender — but for a subcontractor its real life begins after award, because it is the one document that defines what “the scope” means when progress, payment, and change are discussed.
The terms, untangled
BOQ (bill of quantities) — the priced, itemised scope: descriptions, units, quantities, rates. Common in UK, Commonwealth, European, and Middle Eastern contract forms.
WBS (work breakdown structure) — the hierarchy the items live in: sections, systems, areas. The BOQ says what and how much; the WBS says where it sits in the job. In practice a subcontractor works with both at once — a structured, priced scope.
Schedule of values — the US counterpart: the contract price broken into line items for payment purposes, usually without measured quantities.
Remeasurement vs lump sum — under remeasurement, payment follows the quantities actually executed at the agreed rates; under lump sum, the price holds and the BOQ is the basis for valuing progress and change rather than for remeasuring the total.
Why the BOQ is the baseline, not the archive
The most expensive thing a subcontractor can do with a BOQ is file it. The moment progress is tracked in one spreadsheet, hours in another, and claims in a third — each with its own row structure — the records begin to disagree, and the version the client believes is rarely the one that pays more. Kept alive as the working baseline, the same BOQ structure carries the whole job:
- Progress — physical completion is measured per BOQ item, in the item’s own units, week by week. “Percent complete” then has a defined meaning: quantity done against quantity contracted.
- Labour — the budgeted man-hours of the contract are distributed across the items, so manpower planning is checked against the labour base of the scope, and completed work earns hours for the efficiency calculation.
- Money — progress claims are derived from the same items: cumulative value of work done, minus what was previously certified. Every claim line points back to a contract line.
- Change — variations and extra work enter as separate, named items with their own approval trail, so original scope and added scope never blur.
One structure, four uses. When the client’s quantity surveyor asks why item 3.2 is claimed at 80%, the answer is a record, not a reconstruction.
What a workable BOQ looks like in practice
- Items measurable on site. If the site team cannot say what quantity of an item was done this week, the item is too coarse to track — or worded for pricing, not for measurement.
- One import, one truth. The BOQ arrives once (usually from Excel) and becomes the reference. Copies-of-copies with drifting formulas are how scope quietly forks.
- Sections that match how the job is run — by system, area, or discipline — so progress and manpower can be read per section, not only per line.
- Rates left intact. The commercial content of the BOQ is the entitlement. Working documents that strip or overwrite rates eventually cost real money.
Frequently asked questions
What is the difference between a BOQ and an estimate?
The estimate is the contractor's internal calculation of what the work will cost; the BOQ is the contractual list of items, quantities, and rates the parties agree to measure and pay against. The estimate can be wrong privately. The BOQ is the document both sides point at when money is discussed.
What is the difference between a BOQ and a schedule of values?
They serve the same role in different traditions. A BOQ (UK, Commonwealth, much of Europe and the Middle East) is built from measured quantities and unit rates. A schedule of values (US) breaks the lump-sum contract price into line items, often without measured quantities. Both are the baseline that progress and payment applications are assessed against.
What happens when actual quantities differ from the BOQ?
It depends on the contract. Under a remeasurement contract, the work is paid at the agreed rates for the quantities actually executed, so the BOQ quantities are a best estimate. Under a lump sum, the price holds unless the scope itself changes. Either way, the difference must be visible — which is only possible if progress is recorded against the BOQ items rather than in a separate tracker.
How should extra work appear in the BOQ?
As separate, named items with their own descriptions, quantities, and rates — never typed into original contract lines. Merging extra work into original quantities destroys the entitlement trail: the client cannot certify what they cannot see, and the subcontractor can no longer prove what was original scope and what was added.