🇦🇺 Australia · Construction cost guide · Updated 2026
How much does it cost to build a duplex in Australia?
Building a duplex in Australia typically costs $825,760 to $1,532,960 in construction cost — roughly $1,588–$2,948 per square metre over 520 m² of floor area. That excludes land, professional fees and statutory charges.
Australia is a high-cost construction market by global standards — it ranks 16 of 200 countries on our construction cost index, at about 108% of United States build costs. This page prices a duplex — two-unit dwelling over two floors, shared party wall, separate services to each unit — at 520 m² of gross floor area, then breaks the cost down element by element so you can see where the money actually goes. Costs are quoted in USD for comparability; the local currency in Australia is AUD (A$), and a bill of quantities generated from your own drawings is priced in AUD using the ASMM6 standard.
What is being priced
The figures on this page price a duplex in Australia at 520 m² of gross floor area over 2 storeys, specified as two-unit dwelling over two floors, shared party wall, separate services to each unit. Construction cost only — land, professional fees, statutory charges, utility connections and loose furniture are all excluded, and together commonly add another 15–30%.
Cost by specification level
| Specification | Construction cost (USD) |
|---|---|
| Basic / low-cost finish | $594,547 – $1,103,731 |
| Standard finish | $825,760 – $1,532,960 |
| Premium finish | $1,197,352 – $2,222,792 |
Where the money goes
Elemental split of construction cost for a duplex of this type. Percentages are concept-stage cost-planning proportions; the ranges below apply them to the totals above.
| Element | Share | Cost (USD) |
|---|---|---|
Substructure & foundations Excavation, strip footings, hardcore, blinding, DPC and ground slab. | 15% | $123,864 – $229,944 |
Walling & superstructure Masonry, lintels, ring beam and any suspended floor. | 22% | $181,667 – $337,251 |
Roofing Trusses or rafters, covering, ceilings, fascia and rainwater goods. | 14% | $115,606 – $214,614 |
Internal finishes Plaster, screed, floor and wall tiling, ceilings and painting. | 18% | $148,637 – $275,933 |
Joinery & fittings Doors, windows, cupboards, worktops and ironmongery. | 9% | $74,318 – $137,966 |
Services (plumbing & electrical) Wiring, distribution board, fittings, water reticulation, sanitaryware and drainage. | 14% | $115,606 – $214,614 |
External works & preliminaries Site setup, supervision, paths, boundary works and connections. | 8% | $66,061 – $122,637 |
Get the real number for your own plans
A benchmark tells you the ballpark. Upload your dimensioned drawings and get an itemised, source-cited bill of quantities priced in AUD (A$), measured to the ASMM6 standard Australia professionals use.
Price my Australia projectBuilding duplexes in Australia — frequently asked
How much does it cost to build a duplex in Australia?
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Building a duplex in Australia typically costs $825,760 to $1,532,960 in construction cost — roughly $1,588–$2,948 per square metre over 520 m² of floor area. That excludes land, professional fees and statutory charges. At a basic specification the same building lands nearer $594,547–$1,103,731; at a premium specification, $1,197,352–$2,222,792.
What is the cost per square metre in Australia?
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About $1,588–$2,948 per m² for this building type at a standard finish. Per-m² rates rise with storey height (frame, cores and cranage) and with specification, and fall on simple single-storey plans.
What is the biggest cost item?
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Walling & superstructure — about 22% of construction cost, or $181,667–$337,251 on this build. Masonry, lintels, ring beam and any suspended floor.
Does this include land, fees and furniture?
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No. These are construction costs only — materials, labour, plant and site preliminaries. Land, statutory approvals, professional fees, connections, landscaping and loose furniture are all additional, and together commonly add 15–30% on top.
How do I get an accurate figure for my own plans in Australia?
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Benchmarks give you the ballpark; a measured bill of quantities gives you the number. Upload your dimensioned floor plans to Enormous Buildings and get an itemised, source-cited BoQ in AUD in the ASMM6 format that Australia quantity surveyors and lenders expect — free to preview.
Why do build costs vary so much between countries?
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Three things dominate: labour cost, how much of the material basket is imported, and the code requirements the building must satisfy. Australia sits at index 108 against the United States at 100, which is why the figures above differ from what you'd see quoted for the same building elsewhere.