Working out how much carpet you need comes down to accurate room measurements, understanding how carpet is sold in NZ, and adding a sensible waste allowance. Get this right and you'll avoid costly shortfalls or paying for far more carpet than you need.
How Carpet Is Sold in New Zealand
Most carpet in NZ is sold by the linear metre off a roll that is typically 3.66 m wide (sometimes 4 m wide for certain products). This means you're not simply buying square metres — the width of the roll affects how the carpet is laid and how much you need to order. Always confirm the roll width with your supplier before calculating quantities.
Step 1 — Measure Each Room
Use a steel tape measure (not a cloth one, which can stretch) and measure in metres to two decimal places.
- Measure the length and width of each room at the widest points, including any alcoves, wardrobes, or bay windows that will be carpeted.
- For L-shaped or irregular rooms, break the space into rectangles, calculate each section separately, then add them together.
- Note the direction you want the carpet pile to run — this affects how strips are cut and joined.
Quick formula
| Room | Length (m) | Width (m) | Area (m²) |
|---|---|---|---|
| Lounge | 5.50 | 4.20 | 23.10 |
| Bedroom 1 | 3.80 | 3.60 | 13.68 |
| Hallway | 6.00 | 1.20 | 7.20 |
Add all room areas together for your total floor area in m².
Step 2 — Convert to Linear Metres
Because carpet comes on a roll of fixed width, you need to work out how many linear metres of roll are required, not just the square metre total.
Formula: Linear metres = Room width ÷ Roll width, rounded up to the next whole strip × Room length
For example, a room 4.20 m wide using 3.66 m wide carpet needs two strips (one full strip plus a narrower second strip). You'd order 2 × the room length in linear metres for that room.
This is where it gets tricky — a qualified quantity surveyor or experienced carpet retailer will do this calculation for you and can often save you money by planning the layout to minimise waste.
Step 3 — Add a Waste Allowance
Always add extra for:
- Cutting and trimming around skirting boards, doorways, and corners — allow at least 5–10% on straightforward rectangular rooms.
- Pattern repeats — if your carpet has a pattern, strips must be matched up. The larger the repeat, the more waste. Ask your supplier for the pattern repeat measurement and factor this in for every additional strip.
- Stairs — each tread and riser is measured individually. A standard flight of 13–15 stairs can use a surprising amount of carpet; get a specific measurement from your installer.
- Future repairs — some homeowners keep a small offcut for patching later.
Step 4 — Measure Stairs Carefully
For stairs, measure the tread depth (horizontal surface) plus the riser height (vertical face) and add them together. Multiply by the stair width, then by the number of stairs. Add 10–15% for waste and tucking. Stairs are one of the trickiest areas to estimate — a professional measure is strongly recommended here.
Step 5 — Get a Professional Measure
Most reputable NZ carpet retailers and flooring specialists offer a free in-home measure and quote. This is worth taking up, as a professional will:
- Identify the most efficient laying plan to reduce joins and waste
- Account for doorways, thresholds, and transitions to other flooring
- Advise on underlay thickness (which affects the final floor height and can matter at doorways)
- Confirm subfloor condition, which can affect installation costs
A quantity surveyor can also provide an independent material take-off if you're managing a larger renovation or new build and want a second opinion on supplier quotes.
Underlay — Don't Forget It
Underlay is measured and priced separately. It is generally cut to the same floor area as the carpet (you don't need the same roll-width calculation — underlay is butted and taped at joins). Budget for underlay as an additional cost on top of your carpet.
Rough Cost Guide
As a very broad guide only, carpet in NZ can range from around $30–$40/m² for budget options up to $150/m² or more for premium wool carpet, excluding underlay and installation. Prices vary significantly by product, region, and supplier — always get at least two or three quotes. You can find qualified flooring professionals and quantity surveyors on tradedirectory.co.nz.
When to Call a Professional
Carpet installation itself is not restricted work under the NZ Building Code, so homeowners can legally lay their own carpet. However, poor installation can void product warranties and lead to premature wear, lifting, or trip hazards. For most homes, hiring a qualified carpet layer is well worth the cost. If your project involves:
- Stairs (trip hazard risk if poorly fitted)
- Large open-plan areas with long joins
- Patterned carpet requiring precise matching
- A new build or major renovation where a Licensed Building Practitioner is overseeing work
…then a professional installer is strongly recommended. A quantity surveyor can help you verify that supplier quotes are based on accurate take-offs and fair material quantities.
Site Safe
Licensed Building Practitioner (LBP)
ISO 9001 / 45001 / 14001
NZ Institute of Building (NZIOB)
