The Simple Guide to Measuring and Ordering Your Stair Treads

Ordering new stair treads sounds straightforward until you discover that a few millimetres can affect the fit, finish and installation. Accurate measurements are especially important when replacing existing treads or ordering custom timber stair treads, because the new tread needs to work with the existing staircase rather than simply look right on paper.

This guide explains how to measure stair treads, which dimensions you need, how to measure replacement treads accurately, and what to check before placing an order. If you are considering a complete staircase solution rather than individual treads, you can also explore pre-fabricated stairs designed for faster installation and consistent fit.

Why Accurate Stair Tread Measurements Matter

The right stair tread dimensions depend on more than the visible top surface. Your staircase may have existing stringers, risers, nosings, rebates or other construction details that affect the available space.

An incorrect measurement can result in a tread that is too short, too narrow or too thick for the intended installation. Ordering based on an assumption such as "most stairs are the same size" is therefore risky.

For a replacement project, measure the existing staircase rather than relying on an old plan, previous order or nominal product size. If the staircase is being newly constructed or substantially altered, the overall stair design should also be checked against the applicable National Construction Code requirements and relevant state or territory rules. The Australian Building Codes Board notes that the NCC is given legal effect through each jurisdiction's building regulations, so requirements can vary by location.

What Measurements Do You Need for Stair Treads?

For most timber stair tread orders, start by recording four key dimensions:

Stair tread width

Stair tread width is measured from one side of the tread to the other. Measure at more than one point, particularly if the staircase is old or appears slightly irregular.

If the width changes along the tread, record the smallest and largest measurements. Do not automatically assume the tread is perfectly square.

Stair tread depth

Stair tread depth is the front-to-back measurement of the tread. Be clear about whether you are measuring the physical timber component or the stair's regulatory "going", because these are not always identical.

The NCC defines going using a specific measurement method. For standard residential stairs covered by the Housing Provisions, the permitted going range for stairs other than spiral stairs is 240 mm to 355 mm, with corresponding riser and slope relationship requirements.

Stair tread thickness

Measure the actual thickness of the existing tread with a tape measure or, preferably, a vernier calliper where greater accuracy is needed.

Thickness matters when replacement treads are being installed over or into an existing staircase. Increasing the tread thickness without accounting for the finished stair levels can affect the relationship between the treads and risers.

Nosing or overhang

Measure how far the existing tread projects beyond the riser or supporting structure. This detail is easy to overlook, particularly when measuring an existing staircase from above.

Record the nosing separately rather than assuming it is included in the overall depth.

How to Measure Your Existing Stair Treads

If you are wondering how to measure stair treads for replacement, use this process:

1. Remove anything that hides the actual tread. -  Carpet, trim or other coverings can make the visible dimensions misleading.

2. Measure the width -  Take measurements at the front, centre and rear where practical.

3. Measure the depth -  Record the physical tread depth from the front edge towards the rear.

4. Measure the thickness -  Check the actual timber thickness rather than relying on a nominal description.

5. Measure the nosing - Record the front projection separately.

6. Check the staircase for variation -  Measure several treads, not just the first one.

7. Record every measurement clearly -  Note the step number and whether it is a standard tread, landing tread, winder or another configuration.

This last step is particularly useful on older staircases. A staircase can look uniform while individual components have been modified or replaced over time.

Understanding Standard Stair Tread Sizes

There is no single universal "standard" stair tread size that fits every Australian staircase. Stair tread sizes vary according to the staircase design, available width, construction method, material and applicable building requirements.

For that reason, a stock tread should not be selected simply because its advertised dimensions appear close to your existing stairs.

When considering stair tread dimensions, separate the product's physical dimensions from the staircase's regulatory dimensions. The NCC's requirements for riser and going relate to the design of the stairway, not simply the size of a piece of timber. The ABCB also requires consistency of risers and goings within a flight in relevant circumstances.

How to Measure for Replacement Stair Treads

First, determine how the replacement tread will be installed. A tread fitted into existing stringers may require different dimensions from one installed over an existing staircase.

Next, check the condition of the supporting structure. A new tread cannot correct an underlying problem with damaged stringers, uneven supports or an incorrectly constructed staircase.

For replacement projects, create a measurement schedule such as:

• Step number

• Width

• Depth

• Thickness

• Nosing projection

• Left/right return, where applicable

• Special shape or angle

• Notes about the existing support

This gives the supplier a clear record and makes unusual steps much easier to identify.

When Should You Choose Custom Stair Treads?

Custom sizing makes sense when your staircase does not match readily available stock dimensions.

You may need custom stair treads when:

• Existing steps have different widths.

• The staircase includes winders or angled treads.

• The required depth or thickness is unusual.

• The tread has returns or other shaped edges.

• You are matching a particular existing staircase.

• A renovation requires a specific finished dimension.

Custom does not mean "measure once and order". Accurate site measurements are even more important because the product is being made to suit the information supplied.

If the staircase is unusual, structural, curved or being substantially modified, have the dimensions checked by the appropriate stair or building professional before ordering.

Common Stair Tread Measuring Mistakes to Avoid

The most common errors are surprisingly simple.

Measuring only one tread: Measure multiple treads to identify variation.

Measuring over carpet or flooring: Coverings can change the apparent depth and thickness.

Confusing tread depth with stair going: They describe related but different measurements. The NCC specifies how going is measured for compliance purposes.

Ignoring the nosing: A replacement tread may need to reproduce an existing projection or accommodate a different installation detail.

Rounding measurements too early: Record actual measurements in millimetres before deciding what final product dimension is required.

Assuming every tread is identical: Older or modified staircases can contain variations that are not obvious visually.

Changing dimensions without checking the whole staircase: Altering tread thickness or geometry can affect riser relationships. Stair dimensions should be considered as a complete system rather than as isolated timber pieces.

How to Order Timber Stair Treads

Once you have measured the staircase, organise the information before requesting a quote.

For how to measure timber stair treads, the practical approach is to provide the stair treads supplier with:

• Timber species or preferred material

• Quantity required

• Width of each tread

• Depth of each tread

• Required thickness

• Nosing or overhang

• Any returns, angles or special shapes

• Whether the treads are replacements or for a new staircase

• Finish requirements, if applicable

For how to order custom stair treads, provide a clear measurement schedule rather than a single overall dimension. Photos can also help communicate unusual details, although they should support rather than replace accurate measurements.

If you are ordering timber stair tread Australia-wide, also confirm delivery requirements, packaging and whether the timber requires acclimatisation or finishing before installation according to the supplier's instructions.

Standard vs Custom Stair Treads: Which Is Right for You?

The simplest decision is based on how closely your staircase matches the available product dimensions.

Standard stair treads can be suitable when the required dimensions closely match an available product and the installation method allows for it.

Custom stair treads are generally more appropriate when the staircase has unusual dimensions, shaped steps, returns or renovation-specific requirements.

The key consideration is not whether one option is inherently better. It is whether the tread dimensions are suitable for the actual staircase and intended installation.

Conclusion

Accurate measurement is the foundation of a successful stair tread order. Start with stair tread width, depth, thickness and nosing, then measure several steps to identify variations before choosing a product.

If you are replacing existing treads, measure the staircase as it actually exists rather than relying on assumed stair tread size or nominal dimensions. If the staircase is unusual or undergoing structural changes, have the design and compliance requirements checked by an appropriately qualified professional.

For hardwood stair treads Australia homeowners, builders and renovators can order with greater confidence when the measurement schedule is complete, consistent and easy for the supplier to interpret. If you are also comparing timber options, explore our guide to choosing the right timber for stair treads before finalising your selection.

Urban Treads can then use those details to help determine the most suitable tread specification for your project.

FAQs

How do I measure stair treads accurately?

Measure the width, physical depth, thickness and nosing of the existing tread. Check several steps rather than measuring only one, and record any differences between them.

What measurements do I need to order stair treads?

You generally need the tread width, depth, thickness and nosing or overhang. For unusual stairs, also record returns, angles, curves and other features that affect the tread shape.

How do I measure stair tread depth?

Measure the physical timber from the front edge towards the rear edge. Do not automatically treat this measurement as the stair's regulatory going, because the NCC specifies a particular method for measuring going.

What size stair tread do I need?

The required stair tread size depends on your existing staircase, construction method and applicable requirements. There is no single tread size that fits every Australian staircase, so measure the actual installation before ordering.

How thick should a timber stair tread be?

The required stair tread thickness depends on the staircase construction, support method and the finished levels you need to achieve. Measure the existing tread and confirm the required specification with your supplier or installer before ordering.