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A bill of quantities is the document that turns your measurements into a price. Here's what it is, what goes in it, and when you actually need one — explained without the surveying jargon.

What a bill of quantities actually is

The term comes from quantity surveying — the professional discipline of measuring and costing construction work. Historically, a quantity surveyor (QS) would produce the BOQ on behalf of a client, and multiple contractors would price against the same document to ensure like-for-like tendering.

That's still how it works on large commercial or public projects. But on the residential and smaller commercial jobs that most trade contractors do day-to-day, the BOQ is simply a detailed price breakdown — something you produce yourself, in whatever format makes sense for the job.

At its core, a bill of quantities answers one question: what does this job consist of, and what does each part cost?

In Australia the document is almost always called a "bill of quantities" or BOQ. In the US and Canada, "schedule of values" or "itemised estimate" is more common. In the UK and Ireland, both "BOQ" and "schedule of works" are used. They all describe the same thing.

BOQ vs quantity takeoff vs estimate — what's the difference?

These three terms are related but distinct. A lot of contractors use them interchangeably and then run into trouble when a client or QS asks for something specific.

A quantity takeoff contains materials and quantities measured from drawings — no prices. It's the measurement process that feeds the BOQ or estimate.

A bill of quantities contains descriptions, quantities, units, rates, and totals — fully priced. It's used for tendering, contracting, valuations, and cost control.

An estimate is a total cost calculation that may or may not be itemised. It's your internal pricing decision and the basis for a quote.

A quote or proposal is a fixed price offered to the client, often with a summary breakdown.

The flow is: takeoff → BOQ → estimate → quote. Each step builds on the last. You can skip the formal BOQ on smaller jobs and go straight from takeoff to estimate — but for anything tendered, contracted, or complex, the BOQ is what keeps everyone on the same page.

What goes into a bill of quantities

A properly structured BOQ has five components for each line item:

Description — what the item is, including material spec and any relevant standard. Vague descriptions cause disputes; specific ones don't.

Unit — how the item is measured: m², lm (linear metre), m³, each (nr), or tonne.

Quantity — how much of it, in the stated unit. This comes directly from your takeoff.

Rate — the cost per unit, covering materials and labour.

Total — quantity × rate. This is what gets summed to produce your overall price.

Beyond the line items, a complete BOQ also includes:

Preliminaries — site setup, scaffold, welfare facilities, insurance, and management costs that don't fit neatly into a work section.

Provisional sums — allowances for work that can't be fully defined at tender stage.

Contingency — a percentage allowance (usually 5–10%) for unforeseen items.

A real example — what a BOQ looks like

Below is a simplified bill of quantities for the roofing package on a residential extension. This is the kind of document a roofing contractor would produce before pricing the job.

Section A — Roofing:

• Breathable roofing underlay, lapped and fixed to rafters | m² | 87 | €4.20 | €365

• 50×25mm treated softwood tiling battens at 345mm gauge | m² | 87 | €6.80 | €592

• Concrete interlocking roof tiles, including all clips and fixings | m² | 87 | €28.50 | €2,480

• Half-round ridge tiles, bedded and pointed in mortar | lm | 14 | €32.00 | €448

• Lead valley gutter, code 4, dressed and fixed | lm | 8 | €85.00 | €680

• UPVC fascia and soffit boards, including all fixings | lm | 22 | €38.00 | €836

• UPVC half-round gutters and fittings, including downpipes | lm | 22 | €42.00 | €924

Section B — Preliminaries:

• Scaffold — erect, maintain, and dismantle | Item | 1 | €1,400 | €1,400

• Skip hire — one 6-yard skip for waste disposal | Item | 1 | €320 | €320

Section C — Contingency:

• Contingency allowance (5% on Sections A–B) | 5% | €402

TOTAL — Roofing package: €8,447

Note: Example only — figures are illustrative, not market rates.

Notice how every line has a specific description, not just a material name. The description determines what's included in the price — and what's not.

When you need a BOQ — and when you don't

Not every job needs a formal bill of quantities. Here's a practical guide:

You probably need a BOQ when:

• The job is being formally tendered — multiple contractors pricing the same scope

• A contract requires a schedule of values or priced breakdown for payment claims

• The project is large enough that variations and cost control matter significantly

• You're working with a main contractor who needs to incorporate your costs into their own BOQ

• A client or QS has specifically requested one

A detailed estimate is usually enough when:

• It's a straightforward residential job you're pricing directly with the homeowner

• The scope is well-defined and unlikely to change

• The job is small enough that your normal quote format covers the detail needed

Even when a formal BOQ isn't required, producing an itemised breakdown internally is still good practice. It means you've checked your numbers before committing to a price — and it gives you something to refer back to if scope creep becomes a conversation.

How to create a bill of quantities

Step 1 — Complete your quantity takeoff. Measure all materials and quantities from the drawings. This is your raw data — without accurate measurements, your BOQ won't be accurate either.

Step 2 — Organise by work section. Group your items into logical sections: substructure, superstructure, roofing, internal finishes, services, and so on.

Step 3 — Write clear item descriptions. For each line item, describe the material, specification, and scope of work. Reference relevant standards where applicable.

Step 4 — Add units and quantities. State the unit of measurement and the quantity from your takeoff. Double-check units — mixing up m² and lm will throw out your whole section.

Step 5 — Apply your rates. Enter your rate per unit — this should reflect your current material costs plus your labour allowance. Keep a rate library so your pricing is consistent.

Step 6 — Add preliminaries and contingency. Don't forget the costs that sit above the work sections — scaffold, plant, waste disposal, insurances, and a contingency allowance.

Step 7 — Total up and review. Sum each section, then review the overall figure before it goes anywhere near a client. Sense-check against your experience — if a number looks wrong, it probably is.

How software makes it faster

The traditional BOQ workflow — scale ruler, spreadsheet, manual calculation — works but it's slow and fragile. Change one quantity and you're recalculating by hand.

Takeoff and estimating software like Assemble Pro handles the mechanical parts automatically:

• Quantities flow directly from your takeoff into your BOQ — no retyping

• Rates from your item library apply automatically when you add a material

• Totals update instantly when any quantity or rate changes

• The BOQ can be exported as a PDF or spreadsheet for the client or QS

The real gain from software isn't just speed — it's consistency. When your rates live in a library and your quantities come directly from your measurements, the same job priced twice will come out at the same number. That's what lets you price confidently and competitively.

Frequently asked questions

What is a bill of quantities in construction?

A bill of quantities (BOQ) is a structured document that lists every item of work, material, and labour needed to complete a construction project — with quantities, units, rates, and totals. It is produced from a quantity takeoff and used for tendering, contracting, and cost control.

What is the difference between a bill of quantities and a quantity takeoff?

A quantity takeoff is the process of measuring and listing quantities from drawings — it contains no prices. A bill of quantities takes those quantities and adds descriptions, units, rates, and totals in a structured format suitable for tendering or contract use. The takeoff feeds the BOQ.

Who prepares a bill of quantities?

On larger projects, a bill of quantities is typically prepared by a quantity surveyor (QS). On smaller residential or commercial jobs, trade contractors and builders often prepare their own BOQ using takeoff software or spreadsheets, without involving a QS.

Do I need a bill of quantities for every job?

No. On smaller jobs, contractors often go straight from a quantity takeoff to a priced estimate without producing a formal BOQ. A BOQ becomes more important on larger or tendered projects, when multiple contractors are pricing the same scope, or when a detailed contract breakdown is required.

What does a bill of quantities include?

A bill of quantities typically includes: a description of each work item, the unit of measurement, the quantity, the rate (cost per unit), and the total cost. It also usually includes sections for preliminaries, provisional sums for undefined work, and a contingency allowance.

What is the difference between a bill of quantities and an estimate?

An estimate is a calculation of the total cost of a job — it may be a single figure or a summary breakdown. A bill of quantities is the detailed line-by-line document that supports that estimate, showing every item, quantity, unit rate, and subtotal. A good estimate is typically built from a BOQ.