Free tool · knockdown rebuild
Knockdown rebuild cost calculator for Sydney (2026)
Estimate the all-in cost of demolishing your house and building a new one in Sydney. Every rate and allowance comes from the published ranges in AUD Build’s 2026 knockdown rebuild cost guide, with sources and dates.
Short answer
A typical Sydney knockdown rebuild costs about A$480,000 to A$1.2 million all-in, before contingency. With this calculator, a 220 m² project-spec home in Western Sydney on a CDC comes to about A$549k–A$889k, including a year’s rent at A$700 a week, and a 280 m² custom home on a sloping Upper North Shore block through a DA comes to about A$1.24m–A$1.70m, including a year’s rent at A$1,400 a week. Construction is the largest item (about A$2,000–A$5,500 per m² depending on location and specification); demolition, approvals, site works, council contributions, the long service levy, HBC insurance and rent make up the rest.
Calculate your estimate
Your estimate
| Item | Range |
|---|
Worked examples
| Scenario | All-in range | Plus 5–15% contingency |
|---|---|---|
| Western Sydney, 220 m² project-spec home, CDC, asbestos allowance, 52 weeks’ rent at A$700 (Blacktown median) | A$549k–A$889k | A$575k–A$1.02m |
| Western Sydney, 220 m² custom mid-range home, CDC, asbestos allowance, no rent | A$639k–A$1.04m | A$671k–A$1.20m |
| Upper North Shore, 280 m² custom mid-range home, DA, sloping block, asbestos allowance, 52 weeks’ rent at A$1,400 (Ku-ring-gai median) | A$1.24m–A$1.70m | A$1.30m–A$1.94m |
Rates and allowances used
| Item | Range used | When it applies |
|---|---|---|
| New home construction (floor area × rate) · Western Sydney · project or medium spec | A$2,000–2,650/m² | Always |
| New home construction (floor area × rate) · Western Sydney · custom mid-range | A$2,565–3,500/m² | Always |
| New home construction (floor area × rate) · Western Sydney · high or premium | A$3,430–4,300/m² | Always |
| New home construction (floor area × rate) · Hills & North Shore · project or medium spec | A$3,200–3,800/m² | Always |
| New home construction (floor area × rate) · Hills & North Shore · custom mid-range | A$3,800–4,500/m² | Always |
| New home construction (floor area × rate) · Hills & North Shore · high or premium | A$4,500–5,500/m² | Always |
| Demolition of the existing house | A$10k–A$40k | Always |
| Asbestos removal | A$2k–A$28k | If asbestos is present |
| Service disconnection and reconnection | A$3k–A$20k | Always |
| Tree removal and arborist reports | A$2k–A$8k | If trees must go |
| Survey, geotechnical, BASIX and structural design | A$8k–A$14k | Always |
| Architectural design and documentation | A$12k–A$40k | Always |
| Approval: CDC | A$3k–A$9k | CDC route |
| Approval: DA | A$5k–A$18k | DA route |
| Engineered footings on reactive clay | A$10k–A$40k | Reactive clay |
| Slope, retaining and benching | A$20k–A$80k | Sloping block |
| Rock excavation | A$15k–A$50k | Rock found |
| External works (driveway, fencing, landscaping) | A$25k–A$70k | Project or custom mid-range spec |
| External works, premium (driveway, fencing, landscaping) | A$55k–A$90k | Premium spec |
| Council contributions (s7.11 / s7.12) | A$3k–A$40k | Always |
| Long service levy (0.25% of construction) | 0.25% | Always |
| HBC insurance (about 1.16% of construction) | 1.158% | Always |
How the estimate is built
- Construction = floor area × the per-m² range for your location and specification. Western Sydney rates combine a Rawlinsons-based builder table and Rawlinsons/RLB benchmarks; Hills and North Shore rates come from a builder working on sloping, constrained sites.
- Every other item uses the low and high ends of the published ranges in the cost guide. The low total assumes every item comes in at the low end; the high total assumes the high end, so most projects land in between.
- The long service levy is 0.25% of construction; HBC insurance uses icare’s metro base rate of about 1.16%. Rent is weeks × weekly rent.
- Contingency of 5–15% (as quantity surveyors advise) is shown separately and not included in the all-in figure.
- Not included: land, pools, landscaping beyond standard external works, furniture, loan costs and price changes after October 2026. Check whether each quote includes GST.
Questions
How much does a knockdown rebuild cost in Sydney in 2026?
About A$480,000 to A$1.2 million all-in for a typical 180–300 m² home, before contingency, according to the published guides compiled in AUD Build’s 2026 cost guide. Premium and architectural rebuilds start from about A$1.2–1.5 million. Use the calculator above to see where your block and specification land.
How accurate is this calculator?
It gives a budgeting range, not a quote. It adds up the low and high ends of dated, published ranges for each cost item. Your survey, drawings, council area and specification decide the real price, so ask for a written quote on the same drawings from every builder.
Why are North Shore rates higher than Western Sydney?
The Western Sydney rates come from builders on flat, standard blocks. The North Shore rates come from a builder measuring habitable floor area on sloping, constrained sites, where footings, retaining and access cost more.
What do most quotes leave out?
Council contributions and temporary rent are the most common omissions; a year renting at the Greater Sydney median of A$800 a week is about A$41,600. Asbestos, rock and retaining are often provisional sums.
How does AUD Build price a knockdown rebuild?
From your survey, brief and drawings, as a written proposal that lists demolition, approvals, site works and allowances. Materials come from AUD Build’s own supply chain platform, www.audbuild.net, and AUD Build clients can log in to check the material unit prices in their quote.
Sources
All ranges, with their sources and dates, are in AUD Build’s 2026 cost guide. Compare builders on the same drawings: see the knockdown rebuild builders and duplex builders comparisons.