Stop your grown kids from ruining your retirement

If you are in your 50s or 60s and are still caring for your kids financially, you really need to start caring for yourself—or you may never be able to afford to retire.

A recent study found more than half of parents who are supporting adult children are "extremely concerned" about saving enough for retirement.

Read More 'Boomerang' kids are ruining their parents' retirement

They should be.

Baby boomers are often providing financial assistance to grown kids when they are in the later stage of their own careers during their prime earning years. When you're 50 or older, you have the opportunity to turbocharge your retirement savings with additional contributions to IRAs and 401(k)s.

The maximum contribution to a 401(k) in 2015 is $18,000 plus a $6,000 "catch-up" contribution if you're 50 or older. You can contribute up to $5,500 in 2015 to an IRA or $6,500 if you're 50 or older.

But many boomer parents may not have the money to fully fund their retirement accounts when their kids are living with them.

Say you spend $500 a month on gas, groceries and the phone bill for your 23-year-old son or daughter. Over 12 months, that will amount to $6,000 that could have gone into your 401(k), IRA, or another retirement savings account. If you're 50, putting an extra $6,000 in your 401(k) account this year could grow that balance to nearly $12,500 by the time you're 65, assuming a 5 percent annual return. Use Bankrate's 401(k) calculator to run the numbers yourself.

Read More Lessons from 401(k) millionaires

To get your kid off your couch—and on their own two feet—financial advisors say you should do three things now:

Set a time limit. You don't want your children living with you indefinitely. Let them know how long they'll be able to stay at home rent-free, when they're expected to find a job and when they'll need to contribute financially to the household.

Spell out expectations. You're not running a bed and breakfast. Come up with a list of household chores your son or daughter is expected to do, even if they can't afford to pay rent.

Create a financial plan. Maybe you never talked about finances with your child. Maybe you don't have a budget yourself. You both need one. Your child should design a road map to become financially independent and your top goal as a parent should be to secure your own financial future.

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