How to Prepare a Bill of Quantities
To prepare a Bill of Quantities, you read the drawings and specification, measure the works into itemised quantities (the takeoff), structure them into sections, and set out each item with a quantity, unit and rate ready to price. A good BOQ lets every tenderer price the same measured scope on a like-for-like basis, which is what makes competitive tendering fair.
Key takeaways
- A Bill of Quantities is prepared in four broad steps: read the drawings, measure the takeoff, structure the items into sections, then price each line.
- The takeoff — measuring the works into quantities — is the slowest and most error-prone step to do by hand, and the one most worth automating.
- A BOQ is organised into a preliminaries section plus trade or elemental sections, with provisional sums and PC items kept separate from firm, measured quantities.
- Checking the finished BOQ against the latest drawings before pricing catches the missed items that quietly become under-prices.
- My Trade Hub generates a structured, editable BOQ directly from your plans, which is designed to prepare a tender-ready BOQ 60-75% faster than measuring it by hand.
What you need before you start
Before you can measure a single item, you need the current drawings, the specification, and ideally a recognised method of measurement to follow so items are described and measured consistently. Working from an out-of-date drawing revision is one of the most common ways a BOQ goes wrong, so confirm you have the latest issue before you begin.
It also helps to know upfront whether the client wants a firm BOQ (fully measured quantities throughout) or expects provisional sums and prime cost items for anything not yet fully designed, such as a kitchen selection or a landscaping allowance. That decision shapes how you structure the document from the first line.
Step 1: Read the drawings and specification
Work through the architectural, structural and services drawings alongside the specification to understand what is being built and to what standard. Note the scope of each trade, any items that will need a provisional sum or PC allowance, and anything unusual that a standard rate would not cover.
Cross-check the drawings against each other as you go — a structural detail that does not match the architectural plan, or a services layout that clashes with a wall shown elsewhere, is far cheaper to catch now than after the BOQ has been priced and submitted. A short list of scope queries at this stage is normal, and worth raising with the client or their consultant before you measure rather than guessing.
- Confirm the drawing revision and specification are the current, coordinated set.
- Note items that are not yet fully designed and will need a provisional sum.
- Note client-selection items — tapware, tiles, fixtures — that will need a PC allowance.
- Flag anything site-specific (access, existing services, contamination) that could affect pricing later.
Common mistake
Measuring from a drawing that has since been superseded. A BOQ is only as reliable as the drawings it was measured from — always check the revision number and date before you start the takeoff.
Step 2: Measure the works (the takeoff)
The takeoff is where you measure the works into quantities — cubic metres of concrete, square metres of formwork or brickwork, lineal metres of pipe, tonnes of reinforcement — following the drawings section by section and trade by trade.
Done by hand, this means scaling dimensions off drawings, running them through a dimension sheet, and totalling each item, which is slow and where transposition errors creep in. A missed dimension or a mis-scaled drawing does not announce itself — it just quietly becomes a missing item further down the line, which is why the takeoff is where the most experienced estimators still spend the bulk of their time. My Trade Hub performs the takeoff from your plans automatically, measuring the works and assembling the measured items into a structured BOQ you can review and adjust.
Step 3: Structure the BOQ into sections
Once the items are measured, group them into sections that mirror how the job will actually be built, so each trade can price its own portion and the client can see clearly where the money sits. Preliminaries always sit in their own section, separate from trade quantities, because they are project-wide rather than tied to a single trade.
| Section | Description | Example items |
|---|---|---|
| 1 | Preliminaries | Site establishment, supervision, insurances |
| 2 | Demolition and earthworks | Excavation, disposal, shoring |
| 3 | Concrete and structure | Footings, slabs, reinforcement |
| 4 | Carpentry and fit-out | Framing, linings, joinery |
| 5 | Services | Electrical, hydraulic, mechanical |
Step 4: Price the BOQ
With the quantities structured, apply a rate to each item; quantity multiplied by rate gives the item total, and the item totals build up to the section and overall tender price. Price preliminaries as their own line items rather than spreading them across trade rates, since they scale with program duration rather than trade quantity.
Keep provisional sums and PC items clearly labelled as allowances rather than firm prices, so the client can see exactly which parts of the total are measured quantities and which are estimates still to be finalised.
Checking the BOQ before you tender
Before the BOQ goes into the tender, check it against the latest drawings one more time, confirm every item is priced against the correct unit of measurement, and make sure preliminaries have not been overlooked next to the more obvious trade items.
A quick cross-check — does the total floor area, wall area or concrete volume look right against the drawings at a glance — catches the kind of gross error that a line-by-line review can miss. It is also worth having a second person review the BOQ where time allows, since a fresh set of eyes on someone else’s takeoff regularly picks up an omission the original estimator has read past several times.
Using the BOQ after the tender is won
A priced BOQ keeps earning its keep once construction starts. The same measured quantities become the reference for valuing progress claims as work is completed, and for pricing variations fairly when the scope changes, because both sides already agree on the rate for each item.
This is one reason it is worth investing the time to get the BOQ right at tender stage — the effort pays off for the life of the project, not just at the point of winning the work.
How My Trade Hub helps with your BOQ
My Trade Hub generates a Bill of Quantities directly from your construction plans. The estimation engine performs the measured takeoff, structures the items into sections, and leaves every line fully editable so you apply your own rates and keep control of the numbers.
Because the slow, error-prone measuring is automated, producing a professional, tender-ready BOQ is designed to take 60-75% less time than measuring it by hand — and the same measured quantities flow straight through to progress claims and variations later in the job. Get started with My Trade Hub — no lock-in contracts.
Frequently asked questions
How do you prepare a Bill of Quantities?
Read the drawings and specification, measure the works into itemised quantities (the takeoff), structure them into sections with a quantity and unit for each, then apply your rates to price it. Software like My Trade Hub can generate the measured BOQ from your plans automatically.
What is the difference between a BOQ and an estimate?
A Bill of Quantities is the itemised, measured list of the works; an estimate is the priced prediction of total cost. A priced BOQ is one way to build an estimate.
Can software prepare a BOQ?
Yes. My Trade Hub prepares a Bill of Quantities from your plans by performing the measured takeoff and structuring the items, which you then price with your own rates — and it stays fully editable.
How long does it take to prepare a Bill of Quantities?
By hand, a BOQ for a mid-sized project can take days, since every item has to be scaled off the drawings and measured individually. Automated takeoff software is designed to cut this to a fraction of the time — around 60-75% faster than measuring manually.
Do I need a quantity surveyor to prepare a BOQ?
Not always. On large or complex projects a quantity surveyor adds real value through independent, defensible measurement. On many smaller and mid-sized jobs, builders and estimators prepare their own BOQ from the plans, increasingly using takeoff software like My Trade Hub to do it quickly.
What units are used in a Bill of Quantities?
Items are measured in the unit that best suits the work — square metres for area (formwork, linings), cubic metres for volume (concrete, excavation), lineal metres for length (pipe, skirting), tonnes for reinforcement, and “item” or “number” for discrete components like doors or fittings.
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