Methodology & disclaimers
DutyStack is a free consumer toolkit for stamp duty, funds to complete, loan repayments and indicative LMI. It is not a broker lead service and does not sell products on the free calculator. This page explains how figures are produced so you can judge when to trust them — and when to stop and call a professional.
Last reviewed 2026-08-21
Independent toolkit — not government
DutyStack is an independent product operated by Harbour Lending (Australia). It is not a government website, not affiliated with any state revenue office, and not a substitute for a conveyancer, licensed broker, or credit licensee. Stamp duty rates, concessions, grants and scheme rules change — always verify figures with the official source before you exchange or settle.
Last reviewed 2026-08-21 · Harbour Lending editorial
Funds & stamp duty
Stamp duty, foreign surcharges where applicable, typical government fees, FHB concessions, FHOG eligibility notes, deposit scenarios (5% Scheme / 10% / 20%), LVR, and an LMI applicability flag. Inputs you choose (state, price, purpose, first-home status, new vs established, foreign purchaser) drive which rate schedule and concession path the engine applies.
Rate table version: 2026-07-ftc. When legislation changes, we ship a new version. Always verify with the state revenue office before you buy — DutyStack is not an assessment notice.
Repayments
Principal & interest uses the standard amortising formula for the rate, term and payment frequency you enter. Interest-only is loan × period rate. You supply the interest rate — we do not scrape live lender offers. Results are educational cashflow maths, not a credit assessment and not a product recommendation under the NCCP.
Offset account
Daily interest on max(0, loan − offset)using a 365-day year (leap years ignored). P&I contractual repayment is set on the full loan and does not fall when offset rises — more of each payment hits principal, so you finish sooner. Interest and time saved compare two runs of the same simulator (offset $0 vs your balance). Offset is assumed constant. Excess above the loan earns nothing. Not a lender schedule.
Indicative LMI
Band estimates by LVR for education only. You can override with a lender figure. 5% Deposit Scheme paths are flagged as typically replacing LMI. We never present an indicative band as a firm insurer quote. Lenders and insurers set the price that matters at approval.
Governance: when we update
Material changes to duty schedules, FHB concessions, grant caps, or Housing Australia scheme settings trigger a rate-table bump and content review on the affected learn hubs and guides. Page-level “last updated” dates show the editorial stamp. If a page lags a budget announcement, treat the official source as correct and tell us via Contact.
What this is not
- Not credit advice under the NCCP
- Not a Revenue Office assessment or settlement quote
- Not a lead form — running the calculator does not require contact details. Emailing a PDF to yourself is optional and is not a broker enquiry.
- Not affiliated with any bank, government agency, or Housing Australia
Ads
DutyStack is free. Display ads (Google AdSense) help cover hosting. Ads sit beside or below long publisher content and the calculator — never inside the input fields, and not on login, signup, or dashboard. Suburb calculator URLs redirect to the state first-home-buyer hub. See Privacy for cookies and personalised advertising.
Official sources
Use these sites to confirm duty, grants and scheme eligibility for your contract. DutyStack models common residential paths for education; the revenue office assessment wins.
- NSW — Revenue NSW
- VIC — State Revenue Office Victoria
- QLD — Queensland Revenue Office
- WA — Department of Finance (RevenueWA)
- SA — RevenueSA
- TAS — State Revenue Office Tasmania
- ACT — ACT Revenue Office
- NT — Territory Revenue Office
- Home Guarantee Scheme — Housing Australia
Methodology: How it works. Corrections: Contact.
Who operates DutyStack
DutyStack (dutystack.com.au) is operated by Harbour Lending, Australia. Contact: hello@dutystack.com.au. Editorial review: Harbour Lending editorial, 2026-08-21.
Harbour Lending is not a bank and does not provide regulated credit assistance through this free consumer site. Broker embed accounts are a separate commercial product — see pricing.