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More than 8% of the US population — roughly 26 million people — live in households with three or more generations, according to US Census data.

These multigenerational households make up 3.7% of all US homes or roughly 4.8 million households.

To capture the growing reality of so many generations living together, Sherry Finkel Murphy, founder and CEO of Madrina Molly, coined a new term that’s likely to gain traction in the coming years: “the triple-decker club sandwich generation.”

The US population grew at its fastest pace in more than two decades in 2024. And while the percentage of multigenerational households has remained relatively stable, the growth of the overall US population means the absolute number of people living in these arrangements has increased significantly.

In other words, even though the share of multigenerational households hasn’t changed much, their impact on American society is growing simply because more people are affected by them.

Finkel Murphy noted that this demographic shift is reshaping family dynamics, influencing housing needs, and creating new opportunities for intergenerational learning, specifically from elder family members.

“It’s a tremendous opportunity to learn from grandparents in a way that maybe you and I did not have that opportunity by the time we met our grandparents,” she said on a recent episode of Decoding Retirement.

According to Finkel Murphy, money is the primary driver of multigenerational living; some 40% are doing so for financial reasons.

Mortgage rates remain elevated at 6.7%, while average homebuilder sentiment is at “poor” levels.

“It is less expensive to maintain whatever household if there are more people sharing responsibility,” she said.

The current housing supply falls short of meeting the older population’s needs. According to the National League of Cities, only 4% of existing housing stock is accessible. Consequently, many older adults are staying in their homes longer than they’d like due to the lack of suitable downsizing options.

“Boomers can’t downsize because nobody is building cottages,” Finkel Murphy said. “So they’re stuck at home.”

That, in turn, limits housing opportunities for younger generations, who face a shrinking inventory of homes to buy.

Another reason for the prevalence of multigenerational households is increasing immigration into the US. In 2023, the US saw its largest increase in immigrant population in more than 20 years, with immigrants now accounting for 14.3% of the US population.