Free Property Development Feasibility Calculator

How to Use This Property Development Calculator

To use this property development calculator, enter six numbers and press Calculate. Every field is pre-filled, so you can run the default example before entering your own figures.

1. Land price: What you are paying for the site, before duty and legal costs. Use your contract price, or the asking price.
2. Build cost: Construction only. Switch to Per m² if you have a rate rather than a total.
3. End sale value: Gross realisation across every dwelling. Use settled comparable sales, not listing prices.
4. Professional fees: Architect, engineer, planner and surveyor, as a share of construction. Default is 9%.
5. Contingency: Your allowance for cost overruns. Default is 7.5%.
6. Program length: Months from settlement to final sale, including the sales period. Default is 18.
7. Press Calculate feasibility. Results stay open and update as you change any input.

Open Advanced options to set acquisition costs, statutory and council costs, selling costs, finance rate, debt share, site area, dwelling count and annual net operating income. The finance rate and debt share drive capitalised interest ($164,706 as default figures). Entering a net operating income unlocks development yield, which applies if you are holding rather than selling.

Four outputs carry the decision.

• Development margin: Colour banded against the market convention, with a verdict beneath it.
• Total development cost: Every cost line including capitalised interest.
• Peak debt: Your highest debt balance and the month it occurs.
• Maximum land price: The residual land value at your target margin, with the headroom against what you are paying.

Read the sensitivity grid before committing. It runs end sale value and build cost 10% either way and shows the margin in all nine combinations. A margin that only holds in one cell depends on every assumption landing.

The Development Feasibility Formula

Development margin is net profit divided by total development cost. The calculator runs three equations in sequence.

End sale value is also called gross realisation or gross development value.

Margin comes in two versions and only the denominator changes. Divide by total development cost for margin on cost, or by end sale value for margin on end value. Check which basis your lender uses.

Run the same formula backwards and it solves for the land price instead of the margin.

Maximum land price = end sale value − all other development costs − your target profit

Set your target margin in Advanced options. Negative headroom means the site does not support the price at that margin.

What Costs Go Into a Property Feasibility?

Seven cost groups, plus contingency. On the default figures, everything other than land and construction adds $582,506, which is 20% of total development cost.

Contingency should fall as the project gets more certain. The calculator defaults to 7.5%, which suits early feasibility. Reduce it once you hold a builder's quote and the design is fixed.

Professional fees typically run 6% to 12% of construction. Smaller projects sit at the higher end, because fees do not scale down with project size.

What Is a Good Development Margin?

An ideal development margin ranges between 15% to 20% on cost is the conventional floor, not the target. Lenders commonly require at least 15% on gross development value before approving development finance.

• Above 20%: The project carries a buffer.
• 15% to 20%: Workable, with no room for a cost overrun or a soft market.
• Below 15%: Too thin once program slippage and cost movement are counted.

Lenders discount developer end sale assumptions, so run your own numbers at a lower end value before you commit. And a feasibility margin is an estimate, so a 16% result can land under the floor without anything unusual happening.

The margin approved at feasibility is the one you then have to hold. Mastt's software for real estate developers tracks budget, commitments and forecast final cost from acquisition through closeout, so the delivered margin stays close to the approved one.

What This Calculator Doesn't Include

This is a screening tool for a first-pass estimate. It excludes anything that would need maintaining per jurisdiction.

• GST and the margin scheme: Not modelled. On a residential project this can move the result by six figures. Treat the output as pre-tax.
• Stamp duty brackets: Entered as a percentage. Rates and thresholds differ by state and change annually.
• Council contributions: A single input. Schedules vary by council and by year.
• Construction rates: Yours to enter. A benchmark rate applied to the wrong site produces a confidently wrong margin.
• Site conditions: Slope, soil, contamination, heritage and demolition sit outside what the inputs can see.
• Planning constraints: No zoning, overlay or approval pathway assessment.

Two structural limits apply.

• Static residual method: Suits screening and small to medium projects. Larger or longer projects need discounted cash flow with monthly modelling.
• Funding and settlement assumptions: Debt is drawn proportionally across every cost line and sale proceeds arrive in a single settlement. Equity usually goes in first and settlements are staged, so the peak debt shown is conservative.

For a sharper build number, use the construction cost estimator.

_{Disclaimer: This calculator gives a high-level estimate for screening only. It is not a feasibility study, a valuation or financial advice, and Mastt accepts no liability for decisions made using it. Seek independent professional advice before committing to a site.}