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Renovation Cost Calculators NZ: Which One to Use and When

Written by

Swati Tiwary

, Superior Renovations

17 October 2021

 • 

13 min read

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Ten free renovation cost calculators, which one fits your job, what every estimate leaves out, and how to turn the ranges into an Auckland renovation budget.

Every renovation cost calculator in NZ answers one narrow question: roughly what does this single job cost? Superior Renovations runs ten of them, from bathrooms and kitchens through to reroofing and louvre roofs, and you'll find every Superior Renovations cost calculator in one place on our tools page. Each one takes a minute or two and gives a price range built from what we charge across more than 1,000 completed Auckland renovations.

What a calculator can't tell you is which tool fits your job, how to add three or four results together, or what sits outside every one of them. The short answer on house renovation cost: in Auckland a standard renovation runs about $2,000 to $4,500 per square metre, and a mid-range full renovation of a three-bedroom home lands around $80,000 to $160,000. The detail behind those numbers is in our room-by-room guide to Auckland renovation costs.

Use the calculators to set a ballpark. Then use the method further down to turn that ballpark into a budget you can put in front of a builder without getting a nasty surprise back.

Every renovation cost calculator and planning tool we run, grouped by the job

Superior Renovations runs ten renovation cost calculators, and our sister brands across Superior Construction Group run calculators and planning tools for the jobs around them. Work out which group your project sits in and you'll know which tool to open first. They're all free, and none of them is a quote: each asks a handful of questions about size, scope and finish, and gives you a range to plan with.

Rooms

More space

The outside of the house

Outdoor living

All ten are on the Superior Renovations tools page.

Cabinetry and joinery, from Little Giant Interiors

If you're running the rest of the trades yourself and only want the joinery priced, these price the cabinetry on its own.

Painting and plastering, from Superior Painters

The right place to go if paint or plastering is the whole job.

Maintenance and upgrades, from Superior Property Services

For the smaller jobs and upgrades that keep a house warm, dry and running, including rentals.

All ten are on the Superior Property Services cost calculators page.

Design, consent and planning, from Sonder Architecture

These answer the questions that come before a price: whether you need consent, what it costs and how long it takes, what design fees look like, and what your site allows.

All ten are on the Sonder Architecture tools page. Any consent answer from a tool is a starting point only; confirm your specific job with Auckland Council or a Licensed Building Practitioner.

Which renovation cost calculator to use when

The calculators are simple. Picking the right one, and knowing when to run two, is where an estimate usually goes off track. This is how we'd match the tool to the job.

One bathroom or one kitchen

This is the straightforward case. If you searched for a bathroom renovation cost calculator NZ-wide and ended up here, bear in mind ours is built on Auckland jobs, so read its range as an Auckland figure. The bathroom tool covers everything from a quick refresh to a full tile-to-ceiling rebuild with underfloor heating, so price a refresh and a full rebuild in the bathroom calculator and look at the gap between them.

The same caveat applies to our kitchen renovation cost calculator: NZ-wide searches find it, but it prices Auckland kitchens. Put your layout and finishes through the kitchen calculator twice: once at the spec you want, once at the spec you'd settle for. The difference between the two numbers tells you which decisions are driving your budget.

In a kitchen, the layout decision is usually the big one. Keep the sink, cooktop and fridge where they are and you're paying for a new kitchen. Move the sink to an island and you're also paying for new drainage and a new waste run.

A kitchen and a bathroom together

Run each room through its own calculator and add the two results. We don't publish a combined rate for doing both at once, so treat the sum as your working figure until a quote says otherwise. Carry the high end of each range forward. The low end assumes nothing unexpected turns up in either room.

Adding space: extension, garage conversion or new garage

The question here is whether the space already exists. If you're turning an existing garage into living space, use the garage conversion tool; if you're adding new floor area to the house, use the extension tool; if you want a standalone garage, use the new garage tool.

Two things move the extension number more than anything else. A ground-floor extension in Auckland runs $2,000 to $5,500 per square metre, and a standard 25 to 45m² addition lands around $160,000 to $280,000. Going up costs more: a second storey runs $4,500 to $8,000 per square metre, roughly 50% more than the same area on the ground floor.

If the garage is becoming a self-contained granny flat, be clear about what the figure covers. Our published range for a single garage of about 30m² converted to a self-contained unit is $110,000 to $145,000, and that's build cost only. Design and consent add $10,000 to $20,000, and Development Contributions add another $5,000 to $20,000.

The outside of the house: reclad, reroof, double glazing

These three are worth running together if any of them is on the cards, because the timing changes the price. Windows replaced during a reclad cost $800 to $1,500 each, against $1,200 to $2,000 each when they're done later as a separate job. Scaffolding on a typical two-storey home runs $10,000 to $20,000, and you'd rather pay for it once than twice. Retrofit double glazing for a whole house sits around $20,000 to $35,000 on its own.

Outdoor living: pergola or louvre roof

The pergola calculator prices a fixed structure by size and materials. The louvre roof calculator prices three different systems by type and size: fixed aluminium screens, a manual louvre kitset, or a fully motorised opening roof. If you want to open and close the roof depending on the weather, go straight to the louvre tool.

What every renovation cost estimate leaves out

A calculator prices the job as you describe it. It can't see inside your walls. The hidden issues common in older Auckland homes, plus consent costs, sit outside every calculator range we publish. In practice that means a few specific lines you'll need to add yourself.

  • Condition behind the linings. Rotten framing behind the GIB, failed waterproofing under a shower, and wiring or plumbing that no longer meets code. None of it is visible until demolition starts, and a 1920s villa in Grey Lynn carries far more of this risk than a 2010s townhouse in Hobsonville.
  • Asbestos. Any home built or renovated before 1 January 2000 may contain asbestos materials. Testing and, where it's needed, licensed removal are their own cost lines.
  • Consent fees. If your job needs a building consent, Sonder Architecture's building consent cost calculator adds the council lodgement deposit, the Code Compliance Certificate and the building levies into one indicative figure. Council fees are cost-recovery, so the final invoice can move up or down from the deposit.
  • Design and engineering. Drawings, engineering and documentation are separate from the consent fee and separate from the build.
  • Living somewhere else. If the work means moving out, temporary accommodation runs about $400 to $800 per week.
  • Items you buy separately. Appliances are the classic example in a kitchen: a separate purchase from the kitchen itself.

Whether your particular job needs a building consent is a question for Auckland Council or a Licensed Building Practitioner, not for a calculator. One more check before you add anything up: some published figures exclude GST, so make sure every number on your list is on the same basis.

How much does it cost to renovate a house in NZ? The figures behind the calculators

If you're doing several rooms at once, it helps to know the whole-home rates the calculators sit inside. These are the renovation costs NZ homeowners can expect per square metre in Auckland, from our own quoting and delivery.

  • Basic or refresh, $2,000 to $2,500/m²: cosmetic work, repainting, flooring, fixture swaps, existing layout kept.
  • Mid-range, $2,500 to $4,500/m²: new kitchen and bathroom, some layout change, mid to upper finishes.
  • High-end or structural, $5,500/m² and up: strip-out, structural change, premium finishes, full services replacement.

By room and by component, the figures we work to are:

  • Mid-range kitchen: $26,000 to $35,000, roughly $2,300/m² for a typical 10 to 12m² space. Large (18m² and up) or premium kitchens run $62,000 to $138,000 or more.
  • Mid-range bathroom: $25,000 to $35,000. A full overhaul with retiling, a new layout and premium fixtures reaches $40,000 to $60,000.
  • Full rewire: $8,000 to $15,000 for a standard three-bedroom home, $20,000 or more for larger or two-storey homes.
  • Full replumb: $10,000 to $20,000.
  • Retrofit double glazing, whole house: $20,000 to $35,000.

Labour is the thread through all of it. Qualified trades in Auckland charge $120 to $150 an hour, and Auckland prices run 10 to 20% above the national average because of higher labour rates and compliance costs. That's why a small room never costs proportionally less: every trade still has to turn up.

Once the list runs to three or more rooms, it stops being a set of calculator results and becomes one project. That's how we scope and price the whole-home renovation work Superior Renovations takes on: one scope, one programme, one project manager, rather than a stack of separate room prices.

Turning a calculator estimate into a working budget

A calculator range is a starting point. To turn one, or several, into a budget you can plan around, work through these five steps.

  1. Run one calculator per job, at two specs. The spec you want and the spec you'd accept. Write both ranges down.
  2. Carry the high end forward. Use the top of each range as your planning figure. The low end is the best case, and older Auckland houses don't often deliver it.
  3. Add the lines no calculator prices. Consent, design, asbestos testing on a pre-2000 home, temporary accommodation, and anything bought separately.
  4. Add a contingency. Budget 10 to 20% on top. On a pre-1940s do-up in Mt Eden or Ponsonby, lean towards 20%.
  5. Check it against what you can fund. If it doesn't fit, trim scope or spec. Don't trim the contingency, because that's the line that keeps a surprise from stalling the job.

A worked example

Say you want a new kitchen and bathroom at mid-range in a 1930s bungalow in Mt Albert. At our mid-range figures, the kitchen sits around $26,000 to $35,000 and the bathroom around $25,000 to $35,000. Added together, that's $51,000 to $70,000.

The house is older than 1940, so add 20% contingency: $61,200 to $84,000. If you move out for six weeks while both rooms are out of action, add $2,400 to $4,800 for accommodation. If the wiring is original, a full rewire is another $8,000 to $15,000, and it's far cheaper to do it while the walls are already open.

The figure to plan with is somewhere between $63,600 and $103,800. The two rooms on their own started at $51,000. Both numbers are honest. One prices two rooms; the other prices a renovation.

Reading quotes against your calculator range

Once you've got a budget, quotes become much easier to read. A quote that lands well under your range has usually left something out: consent, project management, or a contingency the builder is quietly hoping they won't need. Two quotes that look $20,000 apart are often pricing two different jobs. One has quoted a full rewire; the other has assumed your wiring is fine.

Ask each builder to price the same written scope, then line the quotes up against the list you built above. Any line in your budget that doesn't appear in a quote is a question to ask before you sign. Residential building work of $30,000 or more including GST also needs a written contract, plus a disclosure statement and checklist from the builder before you sign.

A calculator also can't account for how a builder handles changes. Extra power points, a second-thought splashback or a "while you're in there" job are all legitimate, but each one is a variation priced mid-build, and contingency isn't meant to pay for it. Additions you choose are a budget increase. Treat them that way and you'll know where your money went.

From calculator estimate to feasibility report to quote

Our process has three steps, and the calculator is only the first. An online estimate gets you a range; a feasibility report tightens it; an on-site visit turns it into an itemised quote.

Once you have a range, send it through with a request for our free feasibility report. Our architect reviews it remotely, using the property file from Auckland Council, which you'll need to apply for and attach. The report reviews your scope, identifies the key compliance issues and whether resource or building consent is likely, and recommends next steps, costs and potential challenges. You'll hear back within five working days. It's one free report per customer and address, and it's guidance rather than a guarantee of full compliance.

After that we visit, measure up and agree the scope with you, and the estimate becomes an itemised quote. That's where the hidden-condition questions get answered, because someone has actually looked at the subfloor, the switchboard and the back of the shower wall. Our showroom is at 16B Link Drive, Wairau Valley, and our team works across Auckland, from the North Shore through to South and West Auckland.

Renovation cost calculator questions

How accurate is a renovation cost estimate from a calculator?

It's a realistic ballpark, not a quote. Our ranges are built from real costs across completed Auckland renovations, but your final price depends on your home's condition, access, finishes and any consent work. Hidden issues such as rot, asbestos and old wiring sit outside the range, which is why an on-site visit comes before a firm price.

How much does it cost to renovate a house in NZ?

In Auckland, a standard renovation costs about $2,000 to $4,500 per square metre, rising past $5,500/m² for high-end or structural work. A mid-range full renovation of a three-bedroom home lands around $80,000 to $160,000. Add a 10 to 20% contingency, and lean towards 20% on a pre-1940s villa or bungalow.

How much to renovate a bathroom in Auckland?

A mid-range bathroom renovation in Auckland runs about $25,000 to $35,000. A full overhaul with retiling, a new layout and premium fixtures reaches $40,000 to $60,000. Moving the plumbing, the tiled area and the fixture spec move the number most. Our bathroom calculator lets you test a refresh against a full rebuild.

What is the most expensive part of a house renovation?

Room for room, the kitchen. A mid-range kitchen in Auckland costs $26,000 to $35,000, about $2,300 per square metre, and large or premium kitchens run $62,000 to $138,000 or more. On a whole-home job, structural change and full services replacement are what push the rate past $5,500 per square metre.

Got a list of ranges and a budget sheet? Book a free consultation and bring your calculator ranges with you. We'll go through it line by line and point out what's missing before anyone starts pricing. All figures here are indicative ranges, not a quote. Building consent requirements and Restricted Building Work must be confirmed with Auckland Council or a Licensed Building Practitioner for your project.