Does this development stack up?

Ten numbers is usually enough to know whether a site is worth a second afternoon. This calculator takes them and returns margin on cost, profit, peak funding and the month funding peaks, computed by the same appraisal engine that runs inside UpScale.build.

Everything happens in your browser. Nothing is saved, nothing is sent anywhere, and there is nothing to sign up for to use it.

Revenue. Units multiplied by the average sale price, treated as GST inclusive, with one eleventh removed before profit is measured. Every unit settles in the final month of the program.

Land. One site, settling in month one, with no deposit split and no acquisition costs of its own. Transfer duty and legals are not included — price the duty on the development site duty calculator and treat it as a separate line in your own numbers.

Construction and the three percentages. The build as a lump sum, then the conventional charges against it: professional fees and contingency as a percentage of construction, agents as a percentage of gross realisation. Those three defaults are the same ones the product seeds a quick feasibility with, and they are editable because they are conventions, not facts.

Program. The number of months over which costs spread and at the end of which the units settle. It is what turns a cost list into a cashflow, and therefore what produces a peak funding figure at all.

Profit divided by total development cost, as a percentage. Profit is revenue net of GST less every cost including funding costs; total cost is the same denominator. Because both sides move when a cost moves, a $1 increase in cost reduces profit by $1 and raises the denominator at the same time, which is why margin falls faster than intuition expects when a build cost slips.

The calculator also reports margin against the target you enter. It says whether the scheme clears it. It does not say whether the target is the right one — that is a question about your risk, your funder and the market, and no calculator can answer it.

Peak funding is the largest cumulative cash requirement the project reaches — the worst month, measured before any facility is asked to carry it. It is the figure that sizes what you have to arrange, and it is the one a screening spreadsheet most often gets wrong, because a list of costs has no month attached to it.

The month is reported because timing is the thing a total hides. Here every unit settles at the end, so the requirement rises all the way to the month before settlement and the peak equals the whole cost base. Presales, released deposits and staged settlements pull that peak down and forward, and modelling them is most of what separates a screening number from a fundable one.

A note on what this figure is not: it is not a facility balance. It is the project’s requirement, which is what you size the facilities against.

Twelve residential units in New South Wales at $1,450,000 each, on a site bought for $3,300,000, an $8,400,000 build, over 24 months, with professional fees at 8%, contingency at 5% and agents at 2%.

The scheme clears a 20% target by less than half a point. That is a normal screening result, and it is the point at which the numbers stop being a napkin exercise: a 4% build cost increase takes it under, and nothing in this calculation carries the interest that $13.1m of peak funding would actually cost.

It is a screen, not an appraisal. There is no unit mix, no presale cover, no deposit release, no debt or equity structure and therefore no interest, no cost escalation, no BAS cycle and no settlement profile. Those are not oversights — they are the difference between a number you use to decide whether to keep looking and a number you put in front of a funder.

If the answer here is interesting, the two questions that usually come next are what the land can be worth (the residual land value calculator) and how the GST is treated (the margin scheme calculator).