About SmartHL

Why this exists

Most bank calculators tell you one number: your repayment. They rarely show you the part that actually matters — how much of every repayment disappears into interest, how much an offset account really saves, and what date you would genuinely be debt-free.

SmartHL was built to answer those questions. You enter your loan details, and it models the full repayment schedule period by period, so you can see the effect of an offset balance or an extra $100 a fortnight before committing to anything.

How the calculations work

The engine builds a complete amortisation schedule. For each period it calculates the interest charged on the balance (reduced by any offset amount), subtracts that from your repayment, and applies the remainder — plus any extra repayment — to the principal. It repeats until the balance reaches zero.

Because the schedule is built period by period rather than using a single closed-form formula, the effect of an offset account or irregular extra payments shows up accurately, including the compounding benefit over the life of the loan.

What it assumes

Being clear about the limits matters more than looking clever. The model assumes:

• a constant interest rate for the whole term;
• repayments are made in full and on time;
• no establishment, ongoing, redraw or discharge fees;
• no change of loan product, repayment type, or offset arrangement;
• no lenders mortgage insurance, taxes, or government charges.

Real loans deviate from all of these. Treat the output as a well-informed estimate for comparing strategies — not as a prediction, and not as a substitute for the figures your lender gives you.

Your privacy

SmartHL runs entirely in your browser. There is no account, no login, and no server storing your figures. The numbers you type in stay in memory for your visit and are discarded when you close the tab; only the scenarios you explicitly save are written to your browser’s local storage. We never receive either, and could not retrieve them if asked.

That is a deliberate design decision. Home loan details are sensitive, and the safest way to handle sensitive data is not to collect it. Read the Privacy Policy for the full detail.

Independence

SmartHL is a product of Sunshine Tech. It is not a bank, broker, or credit provider, and holds no Australian Financial Services or Credit Licence. It does not recommend lenders, receive referral commissions, or pass your details to anyone. The site may display advertising to cover hosting costs; adverts are supplied by third parties and are not endorsements.

Get in touch

Found a bug, or think a calculation looks wrong? That feedback is genuinely useful — head to the contact page and let us know what you entered and what you expected.