How to Prepare a Bill of Quantities (BOQ): A Practical Step-by-Step Guide

A bill of quantities (BOQ) is the foundation of every construction tender, contract, and progress act. A poor BOQ means a lost tender, a blown budget, and disputes with the investor. Here's a practical 7-step guide to preparing a BOQ, for beginners and for anyone who wants to bring more structure to the process.

What a BOQ is and why it matters

A bill of quantities (BOQ) is a structured document listing all the work on a site, each item with a quantity, unit, unit price, and total value. It's the "language" of construction: the client, the contractor, the designer, and the accountant all read the same document.

A BOQ is used for:

• Tendering - the basis for a fixed price to the investor
• Contract - an appendix to the main contract that defines the scope
• Progress certification - acts for completed work are written against the BOQ
• Budget control - plan versus actual by line item

Errors in a BOQ compound: a wrong quantity in the tender leads to wrong invoicing and a blown budget.

Step 1: Read the project documentation

Before you start counting, read. Mistake number one for beginners is skipping this step.

What to review:

• Architectural drawings (plans, sections, elevations)
• Structural drawings (slabs, beams, columns)
• Technical specifications (concrete classes, reinforcement, materials)
• General conditions (deadlines, warranties, special requirements)

What to ask the designer or investor:

• Concrete class (B25, B30 have different unit prices)
• Reinforcement type (B500B is standard, BSt500S is another)
• Site access (is there a road for trucks)
• Working hours (restricted or not)
• Who supplies the materials (you or the investor)

Don't tender based on assumptions. One unclear detail can throw off the entire offer.

Step 2: Group the line items by category

The structure of a BOQ follows the logic of construction. Here's a standard hierarchy:

1. Preliminary works (mobilization, site clearing)
2. Earthworks (excavation, fill)
3. Structure
   3.1. Formwork
   3.2. Reinforcement
   3.3. Concreting
4. Masonry
5. Roof
6. Finishing works
   6.1. Plastering
   6.2. Screeds
   6.3. Flooring / tiling
7. Plumbing
8. Electrical
9. HVAC
10. Facade
11. Specialized works
12. Demobilization / site clearing

The exact structure depends on the project. It looks one way for a residential apartment and another for an industrial site.

Why use a hierarchy? Subgroup totals make for a quick overview. The investor can see the facade total separately from the structural total and judge more easily whether it fits the budget, without reading through 200 line items.

In Construction Team, the nomenclature catalog follows exactly this logic: groups and subgroups with unlimited nesting depth, one shared catalog for all your bills of quantities, tenders, and contracts. You organize the line items once, at the catalog level, instead of redoing it for every document.

Step 3: Calculate the quantities

This is the most time-consuming part of the job. For each line item, determine:

• Quantity - an exact value, not an approximation
• Unit of measure - sq m, cu m, tons, m, pcs, linear meter
• Description - precise enough to avoid disputes

How to measure different types of items:

Type of work	Metric	Source
Masonry	sq m	Plan area x height, minus openings
Concrete	cu m	Geometry from the drawing
Reinforcement	tons	Rebar schedules x lengths
Formwork	sq m	Contact surface with the concrete
Flooring	sq m	Floor area
Plastering	sq m	Wall plan x height
Electrical points	pcs	Electrical plan

Important: add a waste allowance for every material: offcuts, damaged pieces, delivery errors. The standard percentage depends on the type of work.

If an IFC/BIM model is available, software can read the geometry automatically and save you most of the work in this step.

Step 4: Add the unit prices

For each line item, calculate the final unit price:

Components:

• Materials - including waste allowance and delivery to site
• Labor - wages plus social security contributions
• Equipment - machine rentals, fuel
• Overhead - applied to direct costs (supervision, office, phone)
• Profit - based on your commercial judgment for the project

Where to source prices:

✅ Current quotes from 2-3 suppliers (not a number from a phone call) ✅ Your own price database from similar past projects ✅ A software price list linked to current market rates

❌ Prices "from memory" - the market changes ❌ Prices from a long time ago - materials get more expensive with inflation

In Construction Team, you add each line item directly from the nomenclature catalog, and it comes with a suggested unit price pulled from the linked price list, instead of you having to look up a price by hand every time. You can accept that price or adjust it for the specific project, and once it's on the line, the value stays fixed in the BOQ even if you later change the price in the price list.

Step 5: Contingency reserve and "invisible" items

Totals are calculated automatically by the software. Your job in this step is to decide on two things that can't be automated:

1. Contingency reserve for unforeseen work:

• An additional amount on top of the total, for work that can't be 100% predicted at tender stage (hidden defects in the foundation, design changes, execution-specific issues).
• The size depends on the type of project: for renovations it's usually larger than for new construction.
• It can be shown as a separate line in the offer, or folded into the total price with an explanation.

2. "Invisible" items - often forgotten, but always needed:

• Mobilization / demobilization
• Scaffolding (for facade work and heights above 4 m)
• Temporary facilities (site container, toilet)
• Waste removal
• Lab testing (concrete, soil)
• Surveying
• Design supervision / investor's site control (if it's your responsibility)

Leaving them out is a common cause of budget overruns.

Step 6: Review and correct

Before finalizing, check it yourself and ask a colleague for a second review.

What to check:

• The top 5 highest-value line items - double-check the quantities (this is where the biggest errors hide)
• The top 5 highest unit prices - make sure they're realistic against the market
• Comparison with similar projects - the total price per built-up area should fall within the range of your previous projects of the same type
• Sanity checks - are the totals adding up correctly, is VAT calculated correctly

If you have nothing to compare against (a new type of project), get a second, independent estimate from an experienced estimator or designer.

Step 7: Finalize and export

Once the BOQ is ready:

1. Export it as a PDF with your company logo (for the investor)
2. Keep an Excel copy (for internal work and edits)
3. Archive it in the system for future reference
4. Send it to the investor with a cover letter

In the PDF, include: company details, date, project name, offer validity period, and payment terms.

In Construction Team, once the BOQ is finalized, you can turn it into an offer for the client with a single click, without re-entering the line items. For a contract with a subcontractor, you select the BOQ directly when creating the new contract, so again there's no manual re-entry of items. Versions are kept automatically, so when changes are requested you don't start from scratch.

Common mistakes beginners make

Mistake	Consequence
Missed "invisible" items (mobilization, scaffolding)	Budget overrun
Outdated prices	Margin loss due to inflation
No waste allowance for materials	Actual cost exceeds budget
Wrong unit of measure (m² instead of m³)	Disaster on that line item
No second-person review	One mistake can throw off 1-2 line items
Copying from an old offer without checking	Wrong context, wrong prices

A BOQ in minutes with specialized software

Preparing a BOQ by hand for a large project takes a full working day or more. With specialized quantity survey software:

• IFC/BIM import extracts quantities automatically from the model's geometry
• AI matching links the imported items to your nomenclature catalog
• Prices are pulled from the current price list at the moment you add the line item
• Export to Excel and PDF with a single click
• Versions and history, so when something changes you don't start from scratch
• Converting a BOQ into an offer takes a single click, and into a contract, a direct selection when you create it

The result: a BOQ for a large project takes minutes instead of hours, depending on what input documents you have available.

Related Articles

• Quantity survey software for construction - A full look at the module, beyond the manual process
• How to create a construction offer - The next step once your BOQ is ready
• Causes of construction budget overruns - Why an accurate BOQ is your first line of defense against cost overruns

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