Do you know what your mortgage will cost you? Source: Supplied

Research by comparison website finder.com.au shows that a homeowner with a mortgage of at least $489,300 will end up paying $1 million over the duration of a 30-year loan, using the average variable interest rate of about 5.5 per cent.

Any property priced above $611,625 will end up costing the borrower $1 million, if the mortgage represents 80 per cent of the property’s value.

And if the property is in Sydney, where the median house price is $825,000, borrowers could hit the $1 million mark for their pile of bricks and mortar by just year 11 of the loan.

But, if they buy in Melbourne, where the median house price is $633,000, they won’t hit the $1 million mark until year 24, given a 20 per cent deposit and an interest rate of 5.5 per cent.

The median house price is the midway point of all the houses sold.

In Sydney, borrowers could hit the $1 million mark by just year 11 of the loan. Source: Getty Images

“When borrowers look at how much they can afford to repay for a home loan, they might not look down the track to how much they end up spending,” finder.com.au’s money expert, Michelle Hutchison, said on Monday.

“The danger lies with spending a lot more than necessary.” Ms Hutchison said the value of a house would likely increase over the term of the 30-year loan — but that rise may not compensate for the amount a buyer ends up paying if they have a small deposit and haven’t shopped around for a good interest rate on their loan.

For example, an interest rate of 4.39 per cent — 1.11 percentage points below 5.5 per cent — would save $446 per month in repayments on a home loan of $660,000.

YOUR MILLION-DOLLAR HOUSE*

SYDNEY

Price: $825,000

Mortgage: $660,000

Total cost: $1.349 million

MELBOURNE

Price: $633,000

Mortgage: $506,400

Total cost: $1.035 million

PERTH

Price: $530,000

Mortgage: $424,000

Total cost: $866,673

BRISBANE

Price: $475,000

Mortgage: $380,000

Total cost: $776,735

ADELAIDE

Price: $421,000

Mortgage: $336,800

Total cost: $688,433

*Total cost of a median-priced house with a 20 per cent deposit, over 30 years. (Source: CoreLogic RP Data, finder.com.au)