When two estimators measure the same job from the same drawings and come back with different quantities, the problem is usually not the drawings. It is the measurement method.
Methods of measurement are the agreed-upon rules that govern how construction work gets described, quantified, and priced.
In NZ, we follow the ANZ SMM for this, i.e., the Australian and New Zealand Standard Method of Measurement of Building Works – It’s the shared language that keeps pricing consistent across consultants, contractors, and clients.
This article covers what the ANZ SMM is, how it works in practice, and what happens when measurement goes wrong.
What is the ANZ SMM?
The ANZ SMM is the standard that QS in New Zealand uses when preparing bills of quantities, cost plans, and tender documents. It sets out the rules for how construction work is measured across all building trades, from concrete and masonry through to finishes, fitout, and services.
The standard replaced the older NZS 4202, which some legacy contracts still reference. The current version is ANZSMM 2022, published jointly by the New Zealand Institute of Quantity Surveyors (NZIQS) and the Registered Master Builders Association (RMBA).
For civil and infrastructure work, different guidance applies. The ANZ SMM covers building works specifically.
The core principle: measure net, as fixed in place
The most important rule in the ANZ SMM is this: work is measured net, as fixed in place.
That means no allowances for waste, laps, corrugations, or material bulking. The quantity reflects exactly what ends up in the building, not what gets ordered or delivered.
Take concrete as an example. If you are measuring a suspended slab, you measure the actual volume of concrete in the finished slab. You do not add a waste factor. You do not adjust for over-pour or spillage. Net, as fixed.
Contractors account for waste separately when building up their unit rates. The QS provides the net quantity; the contractor applies their own allowances on top. Keeping these two things separate is what makes tender comparisons meaningful.
Units of measurement
Different building elements use different units. Here are the most common:
- Concrete (slabs, walls, columns, beams): Cubic metres (m3)
- Masonry (brick, block): Square metres (m2), stating thickness
- Timber framing: Linear metres (m) or m3 for large sections
- Steel sections: Tonnes (t) or linear metres (m)
- Floor finishes (carpet, tiles, vinyl): Square metres (m2)
- Roofing (metal, membrane): Square metres (m2)
- Painting and decoration: Square metres (m2)
- Plumbing fixtures: Each (nr)
- Drainage pipework: Linear metres (m)
- Excavation: Cubic metres (m3)
The unit matters because it defines how the contractor prices the item. A subcontractor quoting floor finishes per m2 and a QS measuring in m3 cannot be compared. Getting the unit right from the start prevents that confusion.
What is the difference between gross and net measurement?
Most work under the ANZ SMM is measured net. But the distinction between gross and net comes up regularly when preparing and checking quantities.
Net measurement means the actual quantity of work executed, with no deductions for tolerances and no additions for waste. Concrete in a slab is net. Roof tiles are net. Floor finishes are net.
Gross measurement applies in specific contexts. Building floor area is typically measured to the outside face of external walls (Gross Floor Area or GFA). This is used for cost planning and benchmarking, not for trade-level pricing.
Disputes often start when one party measures gross and another measures net without agreeing on which applies. The ANZ SMM explicitly states the correct basis for each item.
What does a quantity takeoff look like?
A quantity takeoff is the process of extracting quantities from construction drawings and recording them in a structured format. A typical takeoff sheet has these columns:
- Item description: what is being measured
- Dimensions: length, width, depth as read from the drawing
- Quantity calculation: the formula applied (L x W x D for volumes, L x W for areas, L for linear items)
- Unit: m2, m3, m, nr
- Total quantity: the result
Each line traces back to a specific drawing and location. Good takeoff notes show where every number came from, so the measurement can be checked or challenged later.
Most QS work through drawings in a consistent order: substructure first (foundations, ground slabs, drainage), then superstructure (framing, floors, roof), then internal finishes and fitout, then services. Working in a fixed sequence reduces the chance of missing something.
What is the difference between a BOQ and builders’ quantities?
A bill of quantities (BOQ) is a formal pricing document prepared by a professional QS following the ANZ SMM. It lists every item of work in structured sections, with agreed descriptions and measured quantities. All parties price from the same document. The BOQ gets attached to the contract and becomes the basis for progress claims, variations, and the final account.
Builders’ quantities are a shorthand version used internally by contractors and contractor QS. The measurement approach varies from company to company. Builders’ quantities are practical for internal pricing but are not a substitute for a formal BOQ in a tendering process.
The key difference is consistency. A BOQ produced to the ANZ SMM can be compared across multiple tenderers. Builders’ quantities cannot, because the assumptions behind each set of numbers are different. Also, and not to be underestimated, is the set of assumptions as to what is included in a description and hence the unit rate, i.e., is formwork measured separately, are labourers included, etc., etcÂ
Where measurement goes wrong
Most measurement errors are not dramatic. They are small, quiet, and easy to miss until the project is underway.
- Omissions: an item gets missed because it appeared on a detail drawing that did not get reviewed. In a lump sum contract, omissions become the contractor’s problem.
- Wrong units: measuring masonry in m3 when the standard calls for m2. The quantity looks right, but it cannot be compared with subcontractor quotes.
- Gross measured when net required: measuring floor finishes over the full floor area, including walls and columns. The actual installed quantity is smaller.
- Scope gaps between trades: where the concrete frame stops and structural steel starts, or where the builder’s work ends and the mechanical contractor begins. Gaps in scope become gaps in the measurement.
- Unclear descriptions: ‘concrete walls’ tells a contractor nothing useful. ‘Reinforced concrete to external walls, 300mm thick, 35MPa’ can be priced accurately.
Why methods of measurement connect to everything else
Good measurement is the foundation of everything that follows in the commercial management of a project.
Estimates rely on it. If the quantities are wrong, the cost plan is wrong. Variations rely on it. When scope changes, the variation gets valued by re-measurement. If the original measurement was ambiguous, the variation becomes a dispute. Progress claims rely on it. Monthly valuations measure work completed to date against the total. Final accounts rely on it. The reconciliation is only clean if the original measurement was clean.
This is why the ANZ SMM exists. It is not bureaucratic overhead. It is the mechanism that keeps cost management factual rather than argumentative.
How to learn methods of measurement
The ANZ SMM is a learnable skill. It takes time to apply consistently, but the rules are defined, and the method can be practised against real drawings. Importantly, it is broadly adheres to the same principles of measurement, knowing what should be included in any description and what should be measured separately.
NZES teaches methods of measurement as a subject in the Full Estimating and Surveying Certificate, and as a standalone practical course . The standalone course adheres to the ANZ SMM rules, but shows how to apply them as a builder using real NZ construction drawings, and the practical difference between formal QS measurement and builders’ takeoffs.
If you are building a career in construction estimating or quantity surveying, measurement is where the foundation gets laid, and the skills used in tendering with confidence start.
