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APRA DTI Cap Check Calculator
Check whether your new home loan falls within APRA's 20% high-DTI lending cap based on your income and existing debts.
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Australian banks paid more than $55 million in compensation for mortgage offset failures reported to ASIC between September 2023 and August 2025, and ASIC expects that figure to keep climbing as remediation continues. The most common failure in Report 837, published 29 July 2026, is brutally simple: the offset account was opened but never linked to the home loan, so every dollar sitting in it saved nobody anything. Enter your loan balance, offset balance, interest rate and how long the link was broken, and this tool puts a dollar figure on the error before you pick up the phone to your bank.
What ASIC's Report 837 actually found
ASIC reviewed eight banks (AMP, ANZ, CBA, Credit Union Australia, HSBC, ING, Macquarie and Westpac) that together write over 70% of Australia's $2.5 trillion home loan market, examining 204,000 loans settled between March and August 2025. Of the failures the banks themselves identified, 55% were offset accounts opened but not linked, 22% were offsets never opened at all, 14% were linked later than the customer was told, and 9% were other breakdowns. The stakes are large because the money is: Australians held $349.1 billion in offset accounts as of March 2026, up 28% in two years, across roughly 3.3 million mortgaged households.
How to check your own offset in five minutes
Open your banking app first. In the CommBank app, search 'Offset' and select 'Manage my offset' to see exactly which loan the account offsets. In Westpac online banking, go to Service, then Account services, then Manage offset accounts. If the app will not show you the link, call the bank and ask for written confirmation of the date the offset was linked. Pay special attention if you refinanced or switched loan products: those changes are the classic silent link-breakers, and ASIC found some failures went undetected until it started asking questions.
Getting your money back: bank first, then AFCA
Put the complaint to your bank in writing and ask for a remediation calculation covering the full unlinked period, not just the current year. If the answer is slow, partial or wrong, escalate to the Australian Financial Complaints Authority. AFCA is free for consumers and its time limits generally run six years from when you became aware of the loss, so an error from 2021 can still be a live claim. Bring statements: the bank's own daily-interest records decide the final number, and this calculator's estimate tells you whether their offer is in the right postcode.
What the numbers actually mean for you
Why offset failures stay invisible for months
A broken offset produces no alert, no fee line, no bounced payment. Your repayment stays identical; what changes is the invisible split between interest and principal inside it. ASIC's Report 837 (29 July 2026) found exactly this pattern across eight banks holding over 70% of the $2.5 trillion home loan market: some failures surfaced only when the regulator started asking questions.
Of the failures the reviewed banks identified in their own data, more than half were accounts opened but never linked. The customer did everything right, the paperwork existed, and the connection simply was not made.
What the same error costs at different durations
The damage scales linearly with time, which is why detection speed matters more than anything else. Sarah's $110,000 offset at 6.1% leaks $6,710 a year regardless of whether anyone is watching.
Catch it at the first statement and it is an annoyance. Let it ride from a 2025 refinance to a 2027 discovery and it quietly outgrows most people's annual holiday budget.
The five-minute check that beats waiting for a letter
Banks paid over $55 million in offset compensation for failures reported to ASIC between September 2023 and August 2025, and five of the eight reviewed banks ran remediation programs. That sounds reassuring until you read that detection was inconsistent and some banks could not readily tell which customers had even requested an offset.
So check yourself: confirm the offset shows as linked in your app, confirm the linked loan is the right one, and compare two loan statements to see interest fall when the offset balance rises. Do it again after any refinance, fixed-term expiry or product switch, the three events that most often quietly break the link.
Complaining so it actually gets paid
Start with a written complaint to the bank naming the exact period and asking for a full remediation calculation, not a goodwill gesture. Attach your own estimate from this page. If the response stalls or lowballs, the Australian Financial Complaints Authority takes the case free of charge, and its time limits generally allow claims up to six years after you became aware of the loss.
Scale your expectations to your balance, not to headlines. The chart below shows the yearly cost of an unlinked offset at 5.9% across typical balances: a $20,000 offset bleeds about $98 a month, while a $200,000 offset bleeds nearly $1,000 a month. The bigger your balance, the less patient you should be.
The arithmetic of a broken offset
An offset account reduces the loan balance your bank charges interest on. When the link between the two accounts is missing, the bank charges interest on the full loan as if the offset money did not exist. The cost of that failure is just the offset balance, multiplied by your interest rate, multiplied by the fraction of a year the link was broken.
One cap matters: an offset can never reduce your interest below zero, so only the part of the offset balance up to the loan balance counts. The calculator applies that cap first, then works out the yearly, monthly and daily cost so you can match the figure against your own statements.
Calculation Steps:
- Enter your home loan balance and the balance that sat in the offset account over the affected period. Rough averages are fine; the bank's remediation team will use exact daily figures later.
- The calculator caps the offset at the loan balance, because a $700,000 offset against a $500,000 loan only ever offsets $500,000.
- Enter your variable interest rate for the period. If the rate moved around, use the rate that applied for most of the window.
- Enter how many months the offset was unlinked, from the date you asked for it to the date the bank actually connected it.
- The capped offset times the rate gives the extra interest per year; divided by 12 and 365 it gives the monthly and daily bleed, and scaled by your months it gives the total estimate.
Worked example
Sarah refinanced a $540,000 loan in early 2025 and asked for her $110,000 savings to sit in an offset. The bank opened the account but never linked it, and nobody noticed for 14 months. Her variable rate was 6.1%.
Her offset balance is below the loan balance, so the full $110,000 counts. At 6.1%, the unlinked money cost her $110,000 x 0.061 = $6,710 for a full year.
Fourteen months is 14/12 of a year, so the total estimate is $6,710 x 14/12, roughly $7,828. That was $559 leaking out every month, about $18.38 a day, while her app showed a healthy savings balance.
Sarah's bank first offered a $900 goodwill credit. Because she arrived with statements and a $7,800 estimate for the exact window, the complaint went to a formal remediation calculation and settled for $7,340 plus compounding adjustments. The estimate did not need to be perfect; it needed to prove the offer was an order of magnitude off.
Input definitions
Review the glossary of terms used in the calculation model below. Click on highlighted links to read more in-depth definitions in our financial glossary:
| Parameter | Definition & Context |
|---|---|
| Home Loan Balance (AUD) | The variable loan balance the offset should have been linked to. It caps how much of your offset money can actually reduce interest. |
| Offset Account Balance (AUD) | The average balance that sat in the offset account during the broken period. Use a rough average if it moved; the bank's daily records settle the final number. |
| Home Loan Interest Rate (%) | Your variable rate during the affected window. Every dollar of working offset saves interest at exactly this rate. |
| Months the Offset Was Not Working | The gap between when the offset should have been linked (settlement, refinance, or your request) and when the bank actually connected it. |
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