Development Feasibility Calculator - what the site is actually worth

It is the site price that leaves exactly your target profit once every other cost is paid: revenue less construction, professional fees, statutory charges, selling costs, finance and your required margin. Developers bid off it rather than off comparable land sales, because the land is the only cost still open to negotiation once the build cost, the programme and the end values are known. If the asking price sits above the residual, the deal only works if one of the other assumptions moves.

Most feasibility work in Australia uses 20% profit on total development cost as the working hurdle, and financiers commonly want to see at least that before committing to a construction facility, though the number varies with risk, programme length and how much of the stock is pre-sold. Margin on cost measures profit against everything spent; margin on revenue measures the same profit against gross realisation and always reads lower. Compare like with like when someone quotes you a margin.

Sale of new residential premises is a taxable supply, so GST comes off the revenue side. Under the margin scheme the liability is one eleventh of the margin between the sale price and the original land acquisition cost rather than one eleventh of the whole price, which is why the eligibility of the site matters so much to a small project feasibility. This model applies GST to revenue and treats all costs as GST-exclusive, on the basis that input tax credits are recovered.

Peak debt is the largest amount the facility ever has outstanding, usually late in construction just before the first settlements land, and it is the number the lender sizes the loan against. A project can carry a healthy margin and still be undeliverable because peak debt exceeds what the lender will advance against total development cost, typically somewhere near 65 to 75%. Interest is the consequence; peak debt is the constraint.

It follows the same method - a monthly cash flow with an S-curve construction drawdown, capitalised interest, a residual land value solve and a two-way sensitivity grid - at a scale that suits small residential projects of a few dwellings. It does not handle staged releases, multiple land parcels, escalation curves, tenancy schedules or corporate consolidation, which is where dedicated packages earn their licence fee.