LoanLedger

What the mortgage actually costs

Repayments, total interest, and every single payment in the schedule. No signup, no email gate, nothing uploaded.

This is a calculator, not advice. It tells you what the arithmetic does at the numbers you type in. It does not know your income, your other debts or your plans, and it does not recommend a rate, a term or a lender. For advice about your own situation, talk to a licensed financial adviser or mortgage broker.

The schedule is the point

Almost every mortgage calculator gives you one number — the repayment — and stops. That number is the least interesting output. What tells you something is the schedule: the fact that on a thirty-year loan at current rates, the first payment is about four-fifths interest, and it takes the better part of two decades before the balance falls by half. People are routinely shocked by that, and they should be shown it rather than told about it.

So the full schedule is on this page, every payment, no email required. The year-by-year view is the default because 780 fortnightly rows is a lot to scroll; one click expands it to every individual payment.

Fortnightly is not "monthly ÷ 2"

There are 26 fortnights in a year and 12 months. If you take a monthly payment, halve it, and pay that every fortnight, you pay the equivalent of 13 monthly payments a year instead of 12 — a whole extra payment, all of it against principal once the interest is covered. On a $650,000 loan that difference alone typically takes years off the term.

This is why the frequency setting is not a cosmetic preference, and why a calculator that only does monthly is quietly giving New Zealand and Australian borrowers the wrong shape of answer.

What this tool will not do

It will not tell you what you can afford, and it will not recommend a term or a lender. Those require knowing your income, your outgoings and your circumstances, and producing them from a few form fields would be a guess wearing a suit. Worse, it would be personalised financial advice, which is regulated for good reason.

The rest of the toolkit

Fixed term ending?Model the rollover before it lands — the payment change and the interest costExtra repaymentsWhat a lump sum or a little more each payment actually savesCompound interestThe same maths pointed the other way, for saversSuburbIQWhat your borrowing actually buys, by NZ suburb

Questions

Why does it default to fortnightly?
Because that is how most New Zealand mortgages are actually paid, and almost every calculator online defaults to monthly because it was built for the United States. The difference is not cosmetic: 26 fortnightly payments a year is the equivalent of 13 monthly payments, not 12, so paying fortnightly at half the monthly amount clears the loan years earlier. If your loan is monthly, switch it — the setting is right there.
Is the amortisation schedule really the full one?
Yes, every payment, with no email gate. Click 'Show every payment' under the table. Most calculators either hide the schedule or trade it for your email address, which is the actual reason they exist. There is nothing to sign up for here.
Why is there no default interest rate?
Because a rate baked into a static page goes stale, and a stale mortgage rate is not a harmless error — it produces a confident, wrong number for somebody making a six-figure decision. The rate is deliberately an empty field you have to fill from your own loan documents or your bank's current published rates.
Does it handle interest-only?
Not yet, and it will say so rather than quietly producing an amortising figure. If your payment does not cover the interest, the tool tells you the loan would never be repaid instead of returning a number that looks plausible.
Where does the maths come from?
The standard annuity formula, computed in your browser. You can check it: a payment that amortises correctly reduces the balance to exactly zero on the final period, and the schedule shows that. Every figure here is reproducible with a spreadsheet.
Is anything I type sent anywhere?
No. Your loan details are held in your browser's local storage on your own device so they are still there next visit, and there is no analytics script on the page. What you owe is nobody else's business.