Having health insurance shields you from the full brunt of medical expenses, but it's no guarantee that your costs will be low.
Nevertheless, health-care bills still come as a surprise to many individuals who have insurance.
Close to half of adults who bought their own coverage, along with 43 percent of those with insurance through their employer, said they were surprised by the high cost of their most recent health-care bill in the last year, according to a survey from Bankrate.com.
The personal finance site polled 1,000 individuals in July.
"For a lot of people who've had insurance for decades, there's a creeping sensation that more cost is being thrown onto them," said Taylor Tepper, an analyst at Bankrate.com.
Here's why you can still pay massive bills despite having insurance coverage.