Estimate total project cost, required equity, and loan structure for your new build or major renovation.
Built and reviewed by John Pierre Saliba, MFAA Accredited, ACL 511092. Last reviewed 9 October 2026.
These figures are estimates only. Whether a lender funds this project depends on the as-complete valuation and your serviceability, and construction policies differ widely between lenders.
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If the feasibility flag came back green, the next step is pressure testing the two numbers lenders care about most: the fixed-price building contract and the as-complete valuation. I see more construction loans stumble on a soft valuation than on anything else, so before you sign a contract, I can run the project past lenders whose valuers are realistic about your area. If the flag came back red, do not abandon the project yet; a different lender's LVR policy, a revised contingency, or staging the landscaping after settlement often brings it back inside target.
Start with my guide to construction loans to understand progress draws and builder requirements. If you are building two dwellings, duplex construction loans have their own lender quirks worth knowing early, and if you are renovating rather than building new, refinancing to renovate can be simpler than a full construction facility. All figures above are estimates only and subject to lender assessment.
The calculator adds up your full project budget: land value or purchase price, the fixed-price build contract, a contingency allowance calculated as a percentage of the build cost, plus stamp duty, site costs, council and approval fees, and landscaping. Your available equity or deposit is subtracted from that total to find the loan required, and the loan-to-value ratio (LVR) is measured against the total project cost.
The feasibility flag compares your actual LVR against the target LVR you select. If the actual LVR is higher, the calculator shows how much extra equity would be needed to bring the project within target. It also estimates interest payable during construction and a completed value based on a margin over your land and build spend, which varies by build type.
Key assumptions used by the calculator:
This is a general estimate only, not credit advice, a valuation, or a quote. Lenders assess construction loans on the as-complete valuation and a fixed-price building contract, and actual costs and end values vary by project.
If the answer is more than two years ago, there is a fair chance you are paying the loyalty tax. As a guide, a 0.50% rate cut on a $600,000 loan saves about $181 a month. John checks your exact numbers for free, and if staying put is the right call, he will say so.
Typical switching costs run from about $700 to $1,200, covering discharge fees, government registration and a new application. On a $600,000 loan, a 0.50% rate cut saves about $181 a month, so most Sydney refinances recover their costs within three to nine months.
Often, yes, on larger balances. A 0.25% cut on a $600,000 loan saves about $91 a month, roughly $1,095 a year, which typically repays switching costs inside a year. Below that, the case depends on your balance, remaining term and fees; John runs the break-even numbers for you for free.
Most refinances settle within two to four weeks from application. Fast-track digital discharges can be quicker; a slow discharging lender is the most common delay. John manages the whole process, including chasing your current bank.