Land Subdivision Calculator
Run the numbers on your subdivision
Drag the sliders or type your own figures. Stamp duty updates automatically for the state you pick. Switch to Residual Land Value to work out the most you should pay for a site.
Indicative estimate only — not financial, taxation or development advice. Stamp duty uses current general transfer-duty scales and is approximate; confirm with the relevant state revenue office (Revenue NSW, SRO Victoria, Queensland Revenue Office, RevenueSA, RevenueWA, SRO Tasmania, ACT Revenue Office, Territory Revenue Office). For a project-specific feasibility, talk to Blackark.
How to use the subdivision calculator
This tool models a land subdivision the same way a professional feasibility does: it builds a full cost stack, compares it to your gross realisation, and reports the profit and return. Start by selecting the state or territory — stamp duty is calculated automatically on the current general transfer-duty scale for that jurisdiction. Then set your land purchase price, the number of lots, and the expected sale price per lot.
Work down the per-lot costs: construction and civil works, consultants and approvals, council contributions (S7.11 and S7.12 in NSW), and the marketing, sales and conveyancing cost of selling each finished lot. Add a finance assumption (interest rate, project duration and how much of the project is debt-funded) and a contingency buffer. Finally choose how GST applies. The results panel updates instantly with your net profit, return on cost and margin on revenue.
For a deeper walk-through of where these numbers come from, read our guides on how much it costs to subdivide land in NSW and running a full subdivision feasibility study.
What costs go into a land subdivision
Most first-time developers underestimate a subdivision because they only count the land and the civil works. A complete feasibility includes acquisition costs (land plus stamp duty and legals), consultants and approvals (surveyor, town planner, engineers, the DA or CDC), civil construction (earthworks, roads, drainage, services), government contributions, finance and holding costs over the project life, and GST and selling costs at the end. Miss any one of these categories and the deal looks better on paper than it is in the bank.
The order of operations matters. The developers who get hurt are the ones who agree a land price before they know what the civil works, contributions and finance will cost. Run the cost stack first — then make the offer. That is exactly what the Residual Land Value mode in this calculator is for. Read more in S7.11 contributions explained and why subdivisions aren't stacking up in NSW in 2026.
Subdivision calculator FAQ
Internal Rate of Return (IRR) is the annualised return that makes the net present value of all project cash flows equal to zero — in plain terms, the equivalent interest rate your equity is earning over the life of the project. It is more precise than return on cost because it accounts for when money moves: a 25% return on cost spread over five years can produce an IRR below 10%, while the same profit achieved in 14 months produces an IRR well above 20%.
Institutional investors, fund managers and most development financiers set a minimum hurdle IRR — typically 15 to 20% per annum for residential subdivision — alongside the headline return on cost. Both metrics matter: return on cost tells you the size of the margin, IRR tells you whether that margin is worth the time and capital tied up achieving it. This calculator shows return on cost and margin on revenue, which are the right numbers for a fast first-pass read. A full IRR analysis requires a detailed cash flow forecast with drawdown timing, progressive lot settlements and debt servicing, which is part of every Blackark feasibility study.
Want This Run Properly on Your Site?
This calculator gets you a fast, indicative read. Blackark builds full subdivision feasibilities with current civil estimates, indexed contribution rates and real comparable sales across NSW. If you are weighing up a subdivision of any size, we will tell you what it is worth to you before you commit.
From Blackark Insights