Two very different “fortnightly” repayments
True fortnightly is what a lender calculates when you ask to pay every two weeks: it re-amortises the same loan over 30 years with 26 payments a year. For $600,000 at 6.49% that is $1,748 a fortnight — $45,440 a year versus $45,462 on monthly repayments. Interest is charged slightly earlier off a lower balance, so it saves a little: $643 over the loan, and only under a month sooner.
Half-monthly fortnightly is when you set the fortnightly payment to exactly half the monthly figure, $1,894. Because a year has 26 fortnights rather than 24 half-months, you pay $49,250 a year — one extra monthly repayment of $3,788 — and every extra dollar comes straight off the principal. That is where the big saving comes from.
Savings by loan size
| Loan | Monthly | Half, fortnightly | Paid off in | Interest saved |
|---|---|---|---|---|
| $400,000 | $2,526 | $1,263 | 24 years 2 months | $117,110 |
| $600,000 | $3,788 | $1,894 | 24 years 2 months | $175,665 |
| $800,000 | $5,051 | $2,526 | 24 years 2 months | $234,220 |
| $1,000,000 | $6,314 | $3,157 | 24 years 2 months | $292,775 |
6.49% average variable rate, 30-year loan, rate held constant.
Weekly repayments
Paying a quarter of the monthly figure every week ($947) adds up to 13 months a year in the same way, and finishes in about 24 years 1 month — a hair quicker than half-monthly fortnightly because each payment lands sooner. The lender-calculated weekly amount ($874) behaves like true fortnightly: small savings only.
Is it the frequency or the extra money?
Almost all of the benefit is the extra repayment, not the timing. You would get nearly the same result by paying monthly and adding $316 a month (one-twelfth of a repayment). Fortnightly simply makes it painless if you are paid fortnightly, because the money leaves your account before you notice it. Australian lenders calculate interest daily and charge it monthly, so timing on its own changes little.
Checklist before switching
FAQ
Do fortnightly mortgage repayments save money?
Yes, if you pay half the monthly repayment every fortnight. On $600,000 at 6.49% over 30 years that saves about $175,665 and cuts the loan to roughly 24 years 2 months. The lender’s true-fortnightly amount saves only about $643.
Why do fortnightly repayments pay off a loan faster?
There are 26 fortnights in a year, so 26 half-monthly payments equal 13 monthly repayments. The extra month each year goes straight to the principal.
What is the fortnightly repayment on a $600,000 loan?
Half the monthly repayment is $1,894 a fortnight at 6.49% over 30 years. A lender-calculated true fortnightly repayment would be $1,748.
Are weekly repayments better than fortnightly?
Only marginally. A quarter of the monthly repayment each week finishes slightly sooner than half each fortnight, because money arrives earlier, but the difference is small compared with the extra 13th payment both methods create.
Related home loan guides
Assumptions & sources
- RBA cash rate target 4.85%: raised 0.25 points on 3 November 2026, effective 4 November (the Monetary Policy Board voted 6–3). It was the fifth rise of 2026, after February, March, May and September. The Board’s next decision is at 2:30pm AEDT on Tuesday 8 December 2026.
- Average owner-occupier variable rate (P&I) 6.49%: Canstar estimate once the September rise was passed on (29 September 2026), in line with RBA Table F6 — new owner-occupier variable loans averaged 6.23% in August 2026, before the rise. Canstar’s average advertised rate across its whole database was 6.75% (13 October 2026) and the lowest variable rate was 5.89% (20 October 2026). As of 3 November no big-four bank had announced how it would pass on the November rise; passed on in full, it lifts the average to about 6.74%.
- Fixed rates: big-four 1–2 year fixed rates ranged from 6.49% (ANZ) to 6.81% (NAB 2-year) in October 2026; the lowest fixed rate on Canstar was 5.79% (1-year).
- APRA serviceability buffer: 3 percentage points above the loan rate (kept unchanged in APRA’s May 2026 review). From 1 February 2026 no more than 20% of a bank’s new owner-occupier lending (and separately investor lending) may be at a debt-to-income ratio of 6 or more.
- LMI: indicative full-doc premiums from one lender’s table published by Home Loan Experts (updated 18 May 2026); insurers price individually and state stamp duty on the premium may apply (none in NSW).
- 5% Deposit Scheme (First Home Guarantee): Housing Australia rules from 1 October 2025 — unlimited places, no income caps; Darwin cap raised to $750,000 from 1 July 2026.
- Repayments use standard amortisation (monthly, fortnightly or weekly compounding to match the payment) with the rate held constant for the whole term; real loans calculate interest daily and rates change.