The deposit is never the number.
Most people budget the deposit and get blindsided by the rest. Stamp duty alone can be half again what you saved for the deposit. Put your numbers in and see the whole figure before you start looking, not after.
Savings plus any equity you can release. Everything available to complete the purchase.
The contract price you are working to.
Duty is charged where the property sits, not where you live.
Below 20% the lender charges mortgage insurance. It protects them, not you, and you pay it.
Adjust the assumptions
Defaults are typical, not quoted. Replace any of them with a real number the moment you have one.
Your loan
This tells you the cash you need at the table. It says nothing about whether a lender will advance the rest. The borrowing power estimator runs that side of the arithmetic, though the number that finally counts comes from a broker putting your file to a named lender.
Holding costs
Rates, insurance, management, maintenance and the gap between rent and repayments. A purchase you can complete and cannot hold is a worse outcome than one you never made.
Concessions
Figures here use the standard investor rate in each state. First-home and owner-occupier concessions can cut duty sharply and some states remove it entirely. If you will live in it, your number is lower than this.