It’s costing you up to $18,000 to have your adult kid live at home. What to do now to protect your finances

The nest wasn't supposed to stay this full.

A record 25.2 million American adults under 35 now live with their parents, according to Realtor.com . That trend is collectively driven by rising housing costs, high inflation, student debt and a difficult job market, Bloomberg reports .

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For parents absorbing the cost, the financial toll is substantial and frequently underestimated.

According to Savings.com's data , half of American parents with adult kids are providing regular financial support, averaging $1,474 per month, a 6% increase from the prior year. That's nearly $18,000 annually, often with no agreed end date. The breakdown is revealing: 83% help with groceries, 65% cover cell phone bills and 46% are paying for their adult child's vacations .

The retirement damage figure is particularly alarming. Among working parents who financially support adult children, the average monthly contribution to their own retirement savings is just $673, meaning they're putting 2.3 times more into their kids' lifestyle than into their own future. Nearly half of supporting parents say they've sacrificed their own financial security in the process .

AARP found that of 1,744 adults aged 45 and older, 75% are financially supporting at least one adult child, with average annual contributions of approximately $7,000, despite 53% of those children reportedly capable of meeting their own basic needs and then some .

Among those already retired or near retirement, that kind of outflow can permanently reshape the math of how long savings last.

The compounding effect of redirecting money away from retirement at the wrong moment is severe. As finance expert Suze Orman has written on this point : "Every dollar you stop saving for retirement puts your future at risk."

And there's a lot at stake, according to IRS contribution limits: workers 50 and older can make up to $8,000 in catch-up contributions annually on top of the $24,500 standard limit .