Costs, Price Drivers and 2026 Rules
What kitchens, bathrooms, extensions, second storeys and granny flats tend to cost, why, and the state rules that shape every job.
home renovation cost estimator
Home renovation cost estimator for Australian homeowners
Build a realistic budget range for a kitchen, bathroom, extension, granny flat or full refurbishment, then check every quote against the rules in your state.
- Illustrative cost ranges you can adjust, with the arithmetic shown
- State thresholds for licences, written contracts, deposits and home warranty cover
- Quote comparison checklist, contingency and GST calculators
Explore by topic
Worked Estimates and Checklists
Step-by-step estimates, quote comparison, deposits, progress payments, contingency, GST and approval costs.
Mistakes, Disputes and Official Sources
Common renovation mistakes, home warranty insurance, licence checks, consumer guarantees, owner-builder permits and dispute pathways.
Start here
Costs, Price Drivers and 2026 Rules
Bathroom renovation cost in Australia: why small rooms cost so much per square metre
What drives bathroom renovation costs in Australia, illustrative ranges for budget and mid-range finishes, waterproofing rules, strata approvals and quote traps.
Worked Estimates and Checklists
How to compare builder quotes for a renovation and pick the best fit
A practical method to compare two or three Australian renovation quotes like for like, normalising GST, allowances and exclusions, with a worked comparison.
Costs, Price Drivers and 2026 Rules
Home renovation cost estimator for Australia: what drives the price and how to build your range
How Australian renovation costs are built up, the drivers that move them, illustrative ranges by project type and the 2026 rules to check before you sign.
Costs, Price Drivers and 2026 Rules
Kitchen renovation cost in Australia: budget, mid-range and premium explained
What drives kitchen renovation costs in Australia, illustrative ranges by finish level, layout changes, appliance packages and how to read a kitchen quote.
Worked Estimates and Checklists
How to estimate a renovation step by step: from measurements to a budget range
A step-by-step method to estimate an Australian home renovation, with measurements, rate bands, fixed costs, GST, contingency and outside-contract costs, all worked through.
Mistakes, Disputes and Official Sources
Renovation mistakes that cost Australian homeowners money, and the official sources to check
The most expensive renovation mistakes in Australia, from unlicensed builders and oversized deposits to missing insurance, with the regulators and official sources in each state.
Tools
Renovation Cost Estimator
Turn floor area and an illustrative per-square-metre band into a low and high budget range for your renovation.
Renovation Contingency Calculator
Add a contingency percentage and any costs outside the contract to see the budget you should actually plan for.
GST on a Builder's Quote
Add 10% GST to an ex-GST quote and check the GST-inclusive figure you will actually pay.
Builder Quote Comparison Checklist
Line up two or three renovation quotes item by item before you decide which one is the best fit.
Renovation project types compared
| Project type | Typical scope | Approvals usually involved | Main cost drivers | Watch out for |
|---|---|---|---|---|
| Cosmetic refresh | Paint, flooring, lighting, joinery doors, minor repairs | Usually none, unless strata by-laws or heritage controls apply | Area, prep work, product choice | Lead paint in older homes; electrical work still needs a licensed electrician |
| Kitchen renovation | Cabinetry, benchtops, appliances, splashback, plumbing and electrical | Often none for like-for-like; structural or layout changes may need approval | Cabinetry and benchtop material, moving plumbing, appliance package | Low prime cost allowances; walls removed without engineering |
| Bathroom renovation | Strip-out, waterproofing, tiling, fixtures, ventilation | Usually none for like-for-like; strata approval common in apartments | Number of trades per m², waterproofing, tile and fixture choice | Waterproofing done by unlicensed workers; hidden water damage |
| Ground-floor extension | New rooms, slab or subfloor, roof tie-in, services | Development approval or complying development plus building approval | Footings, roof junction, glazing, kitchen or bathroom in the extension | Site classification surprises; stormwater and boundary setbacks |
Frequently asked questions
How accurate is an online renovation cost estimator?
It gives a planning range, not a price. The ranges on this site are illustrative and built from stated assumptions about size, finish level and trades. Real quotes depend on your house, access, structural condition and local labour costs, so use the estimate to decide whether a project is in budget and to test quotes, then get at least two or three written quotes.
Do I need a written contract for a renovation?
In most states, yes, above a set value. In NSW a written contract is required for residential building work over $5,000 including GST, and in Victoria a major domestic building contract is required for most work over $10,000. In Queensland, contracts for domestic building work over $3,300 carry specific requirements. Check your state regulator for the current thresholds.
How much deposit can a builder ask for?
It depends on the state. NSW caps the deposit at 10% of the contract price. Queensland caps it at 10% for contracts under $20,000 and 5% at $20,000 or more, with a higher cap where most of the work is off site. Victoria has capped it at 10% below $20,000 and 5% at $20,000 or more, and reforms that start by 1 December 2026 move the caps into regulations, so check the Building and Plumbing Commission.
What is home warranty insurance and do I pay for it?
It protects you if the builder dies, disappears, becomes insolvent or (in some schemes) has its licence suspended and cannot finish or fix defective work. In NSW it is the Home Building Compensation Fund for work over $20,000, in Victoria domestic building insurance above its threshold, and in Queensland the Home Warranty Scheme above $3,300. The cost is usually built into the contract price.
How much contingency should I add?
There is no legal figure. An illustrative rule of thumb is around 10% for a simple job in a newer home and 15% to 20% for older homes, structural work or incomplete plans. Keep it as a separate line in your own budget, not in the builder's contract.
Is GST included in builders' quotes?
Not always. GST-registered builders charge 10% GST, and some quotes are written ex GST. Always compare GST-inclusive figures and ask for the contract price to be stated including GST.
Who do I contact if a renovation goes wrong?
Raise it with the builder in writing first. Then contact the regulator: Building Commission NSW, the Building and Plumbing Commission in Victoria or the QBCC in Queensland. If it is not resolved, the dispute can go to NCAT, VCAT or QCAT, usually after the regulator's dispute process.
How this site is made
Reno Ruler is an independent information project. Guides are drafted with the help of AI writing tools and checked against official and primary sources before publication; see our Editorial Policy. We are not affiliated with any provider mentioned on the site and do not sell products or services.