By the time you have paid off your mortgage, you may well have handed the bank back twice as much as you borrowed, new research from comparison website finder.com.au has shown.

The research found that Australians with a mortgage of at least $489,300 will end up paying $1 million over the life of a 30-year loan, using the average variable interest rate of about 5.5 percent.

If this mortgage size was 80 percent of the property’s value, that means any property priced from $611,625 will end up costing borrowers $1 million.

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Michelle Hutchison, money expert at finder.com.au, calls this long-term price a “slow-burning hole” in consumers’ pockets.

“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. The danger lies with spending a lot more than necessary.

“While it’s likely that your home will increase in value over a 30-year loan term, it might not compensate the cost of a home loan as the money you end up spending can be greatly increased if you have a small deposit and don’t shop around for a good value deal,” she said.

The research found that Sydney had the most expensive median house price of $825,000, according to figures by CoreLogic RP Data. The average Sydney-sider would hit the $1 million mark after only 11 years.

Melbourne’s median house price of $633,000, meanwhile, would see borrowers with a mortgage of $506,40 paying  $1.035 million over 30 years.

These huge long-term costs show that savvy selection of a mortgage provider could free up significant cash for other purposes. Hutchison urges consumers to shop around for competitive rates.

“This research was based on the average variable rate of about 5.5 percent but borrowers need to remember that there’s a big difference between what lenders are offering, which can mean bigger costs for a home if you’re not careful.

“For instance, the lowest ongoing variable rate on finder.com.au/home-loans is currently 4.39 percent by Heritage Bank – that’s 1.11 percentage points lower than the average variable rate of 5.5 percent and a difference of $446 per month in mortgage repayments for a $660,000 home loan,” she says.