Free Investment Tool
Will a granny flat
pay for itself?
Run your own numbers in 30 seconds. Pick one of our two fixed-price builds, set your rent and loan terms, and watch the weekly cash flow and payback update live — no email required.
Granny Flat ROI Calculator
Pick a build, drag the sliders, and see the cash flow update live. All figures are weekly unless noted.
Choose your build
Default is our appraised rent for this plan. Drag ±40% to match your suburb.
Investment construction loans are typically interest-only. Stress-test +1–2%.
Share of the ex-GST build cost paid as a deposit. All GST is paid in cash; the remaining base cost is borrowed.
Weekly outgoings
If your main house is also rented, adding a granny flat can shave a little off its rent. Model $0–$60/wk.
Your results
Positively geared$33,000
$22,000 deposit + $11,000 GST
$107/wk
on $88,000 borrowed at 6.3% p.a.
$217/wk
rent − repayment − outgoings − main-house adjustment
$11,273
$19,760
34.2%
2.9 years
The only yield figures E2ES publishes are its owner's stated upper range, dated 21 October 2026: a rooming house can reach a gross yield of up to 13% in Melbourne and up to 15% in Queensland. That is an upper range, not a forecast or an expected result — the outcome for any property depends on the site, the rents achieved, vacancy and costs. A granny flat is not a rooming house, and E2ES states no granny-flat yield above that range. No range is stated for New South Wales or Western Australia.
Target rent divided by the build price is not a rental yield: it leaves out the land, vacancy and every holding cost, so we no longer publish that ratio.
This calculator is illustrative only and is not financial, tax or credit advice. Figures are estimates based on E2ES fixed build prices, typical Melbourne rents and an interest-only loan structure; your rent, rate, fees, vacancy, tax position and valuation outcome will vary. Speak to your accountant, mortgage broker and a licensed financial adviser before committing to any investment.
Book a free feasibility chatFrequently asked questions
How accurate is this calculator?
The build prices are our real fixed prices and the default rents are our current appraisals for metro Melbourne, so the starting point is realistic. Your actual result depends on your suburb’s rent, your lender’s rate and fees, and vacancy — treat the output as an indicative model, not a quote or a guarantee.
Why does the calculator not show a yield?
Because rent divided by the build price is not a rental yield — it leaves out the land, vacancy and every holding cost. The only yield figures E2ES publishes are its owner's stated upper range, dated 21 October 2026: a rooming house can reach a gross yield of up to 13% in Melbourne and up to 15% in Queensland. That is an upper range, not a forecast or an expected result — the outcome for any property depends on the site, the rents achieved, vacancy and costs. A granny flat is not a rooming house, and E2ES states no granny-flat yield above that range. No range is stated for New South Wales or Western Australia.
What interest rate should I use?
The default 6.3% p.a. reflects a typical interest-only investment construction loan. Use the rate your broker or lender has actually quoted you, and stress-test the result at 1–2% higher to make sure the cash flow still works if rates rise.
What is not included in the numbers?
The model excludes vacancy periods, repairs and maintenance, land tax changes, depreciation and other tax effects, and any loan setup or refinancing costs on your main mortgage. The cash contribution includes GST. Permits and standard connections are included in the build price; unusual site costs (rock, trees, long service runs) can add more.
Free Site Assessment
Start with a
30-minute site visit.
Tell us your address and the layout you have in mind. We’ll review council overlays and site requirements, then discuss your design, scope and quote. No obligation.
Sales & Feasibility
+61 480 099 909
enquiries@e2es.com.au
Office
Suite 631, Waterman Workspace, 44 Lakeview Drive, Scoresby VIC 3179