About a third of family caregivers spend more than 30 hours a week on caregiving, a new survey shows.

About a third of family caregivers spend more than 30 hours a week on caregiving tasks, a new survey shows. And about a third spend more than $10,000 a year on caregiving expenses, such as medications, medical bills, in-home care and in some cases senior housing.

“The uncovered cost of caregiving often catches people by surprise,” says Andy Cohen, CEO of Caring.com, a website for family caregivers. “It is something they haven’t planned for and budgeted for.”

The findings are based on an online survey of 1,345 visitors to Caring.com. Most of the respondents are taking care of a parent, and some are taking care of a spouse, significant other or relative. “It’s often people in their 50s and 60s caring for parents who are in their 80s and 90s,” Cohen says.

The survey found that 46% of family caregivers spend more than $5,000 a year on out-of-pocket caregiving expenses; 32% spend less than $5,000; and 21% don’t know how much they spend. About 7% spend $50,000 or more a year. “Those people are probably paying for a senior living community,” Cohen says.