The Duplex: What The Numbers Look Like

A well-executed luxury duplex in Blacktown or Seven Hills — five bedrooms, three bathrooms, Torrens title, high specification finishes — is currently selling for $1.45 million to $1.75 million per side.

Let's use a conservative $1.55 million per side.

Duplex project — rough numbers:

• Gross Realisation Value: $3,100,000 (2 x $1,550,000)

• Land cost: $1,200,000

• Construction (Class 1a, ~520sqm): $1,250,000

• Soft costs, contributions, selling: $200,000

• Total Development Cost: approximately $2,650,000

• Net profit: approximately $450,000

• Margin on cost: approximately 17%

The duplex has one significant advantage: it is simpler. Class 1a construction is cheaper and faster. You can often get CDC approval in 20 days, bypassing council entirely. And there is deep buyer demand for Torrens title duplexes from owner-occupiers and investors alike.

The risk is also lower. If the market softens, a $1.55 million duplex half still finds a buyer faster than a $1.2 million townhouse.