Weekly mortgage repayments: true weekly vs a quarter of monthly

Weekly repayments only shorten your mortgage if you pay a quarter of your monthly repayment every week. A "true" weekly repayment, worked out over 52 weeks a year, costs almost exactly the same as monthly and finishes on the same date. On a $600,000 loan over 30 years at 5.06% (the average one-year fixed rate, rates as at 10 November 2026), monthly is $3,242.97 and true weekly is $747.87. A quarter of the monthly is $810.75 a week. Because 52 weeks hold 13 lots of four, that pays one extra monthly repayment a year, finishes in about 25 years and 2 months, and saves about $105,125 of interest. If you are paid weekly, a true weekly repayment can still make budgeting much easier.

What a true weekly repayment is

When you ask your bank to repay weekly, it recalculates the repayment using 52 repayments a year over the same term. The formula is the same one used for monthly loans (see how mortgage repayments work), just with a weekly interest rate and four and a bit times as many repayments. BNZ says that for weekly loans "we calculate interest based on the number of days in those repayment periods", which is 7 days.

The result is a repayment that keeps the loan finishing on the same date as monthly repayments would. It is not the monthly repayment divided by four. A month is about 4.33 weeks, not 4, so the true weekly figure is close to the monthly repayment x 12 / 52. On our example that rough check gives $748.38, against the true weekly figure of $747.87.

Many banks work out weekly interest over the actual 7 days at the yearly rate divided by 365. On our example that gives about $746.69 a week, a dollar or so below the simpler figure. Either way, the loan still takes 30 years.

A quarter of the monthly: the extra repayment hiding in the calendar

If instead you take the monthly repayment and pay a quarter of it every week, you pay 52 quarters a year, which is 13 monthly repayments. That 13th month is an extra repayment, and all of it goes off the principal. ANZ's handbook describes the same effect for fortnightly repayments: "you will be paying the equivalent of one extra monthly repayment a year".

All three are run through our engine at 5.06% for the full term. The quarter-of-monthly option pays $3,269.76 a year more than true weekly, finishes after 1,310 weeks instead of 1,560, and saves about $105,125 compared with true weekly (about $105,949 compared with monthly).

True weekly on its own saves only about $824 over 30 years compared with monthly. That small gain comes from paying a little sooner on average, not from paying more.

Weekly or fortnightly?

A quarter of the monthly each week and half the monthly each fortnight do almost exactly the same job: both add one monthly repayment a year. On our example the fortnightly version saves about $104,855 and the weekly version about $105,125, and both finish in about 25 years and 2 months. Paying weekly gets money off the balance a few days sooner, which is worth a few hundred dollars over the life of the loan, but the frequency matters far less than the extra money. Our fortnightly vs monthly guide has the fortnightly figures.

Weekly repayments by loan size

All at 5.06% over 30 years. At any loan size, a quarter of the monthly finishes in about 25 years and 2 months at this rate, because the extra is always one monthly repayment a year. Our repayment calculator shows the figures for your own loan, rate and term.

Budgeting with weekly pay

For anyone paid weekly, the real advantage of weekly repayments is that the mortgage leaves your account in step with your pay. A few things are worth knowing.

The five-payday months

A year with 52 weekly paydays has 48 of them spread four to a month and four left over, so four months each year have five paydays. If you repay monthly from weekly pay, you need to set aside the right amount each week. Setting aside a quarter of the monthly repayment ($810.75 on our example) means you will build up an extra $3,243 or so over the year, which is fine if you then pay it off the loan, but can leave you short of spending money if you did not mean to save it. Setting aside the monthly repayment x 12 / 52 ($748.38) matches the yearly cost.

Line up the repayment date

Ask for your weekly repayment to come out a day or so after your pay goes in. That avoids dishonour fees and keeps the money from sitting in a transaction account.

Small weekly extras add up

Weekly repayments make it easy to round up. Adding $50 a week to the true weekly repayment on our example saves about $87,186 of interest and clears the loan in about 26 years, if the rate stays the same. On a fixed rate, check the extra fits your bank's allowance: ANZ lets you increase repayments by up to $250 a week (the first increase each year), and BNZ and Kiwibank allow up to 5% of the loan a year. We have not confirmed ASB's or Westpac's allowances. See our extra repayments guide and try amounts on the extra repayments calculator.

Watch for changes at refix

When a fixed term ends, the bank recalculates the repayment on the new rate. If you were paying a quarter of the monthly, ask the bank to keep a higher figure, or it may reset you to a true weekly repayment. Our refixing guide covers what to check.

Is weekly right for you?

Weekly repayments tend to suit people who:

• are paid weekly and like the mortgage to move with their pay;
• want to pay a quarter of the monthly to finish sooner, in small, regular amounts;
• prefer to see the balance fall a little every week.

You do not have to wait for a new loan to change frequency. Kiwibank, for example, says you can change your repayment amount or frequency during a fixed term, and other banks have their own processes. If your loan is split into parts, ask whether each part can repay weekly, so the whole mortgage moves in step with your pay.

Monthly can suit people paid monthly, or who find one large automatic payment easier to manage. Either way, the yearly cost of a true weekly and a monthly repayment is almost the same; the saving only comes from paying more.

This guide is general information, not financial advice. Rates as at 10 November 2026, from the interest.co.nz table. The examples assume the rate stays the same for 30 years; on a real loan it will change at each refix.

Questions people ask

What happens to my weekly repayment when I refix?

The bank recalculates it on the balance and years left at the new rate. If you have been paying more than the minimum, ask the bank to keep the higher amount, or it may reset you to the new true weekly repayment.

Is a weekly repayment just the monthly divided by four?

No. A month is about 4.33 weeks, so a true weekly repayment is close to the monthly x 12 / 52. On $600,000 at 5.06% over 30 years that is $747.87, not $810.75. Paying $810.75 a week is the same as paying one extra month a year.

How much does paying weekly save?

A true weekly repayment saves only about $824 over 30 years on our $600,000 example. Paying a quarter of the monthly each week saves about $105,125 and finishes about 4 years and 10 months sooner.

Is weekly better than fortnightly?

Only slightly. A quarter of the monthly each week and half the monthly each fortnight both add one monthly repayment a year. On our example the weekly version saves about $270 more over the life of the loan.

Can I change to weekly repayments on a fixed rate?

Changing frequency is usually allowed. Kiwibank, for example, says you can change your repayment amount or frequency during a fixed term. Paying more than the minimum counts as an extra repayment, so keep within your bank's allowance.