Tiny apartments are becoming a dominant fixture in urban housing pipelines across the United States, as cities look to combat housing shortages and affordability crises by loosening zoning restrictions and embracing smaller living spaces.

According to a new report from StorageCafe, micro-apartments—defined as residential units measuring 441 square feet or less—are increasingly present in new multifamily construction projects. While the national share of these units among all new apartments has slightly declined from 2.5% in 2022 and 2023 to 2.4% in 2024, the long-term trend reflects a significant increase from just 1.1% in the 2000s and 1.6% in 2018.

In certain urban hubs, micro-units are no longer a fringe phenomenon—they're mainstream. In Seattle, a striking 66% of new apartments underway are classified as micro-apartments. Boston follows closely behind at 56.2%, while Newark, New Jersey, rounds out the top three with 49.8%, according to Yardi Matrix data cited in the report.

These figures reflect broader efforts in U.S. cities to address the intersecting challenges of limited land, surging demand, and stagnant housing supply. In recent years, municipalities such as Boston, Washington, D.C., Denver, Houston, and New York City have revised their zoning laws to accommodate smaller units. The motivation is clear: increasing housing density and expanding the availability of more affordable rental options.

Seattle, in particular, is emerging as a model for micro-housing expansion. The city enacted zoning reforms in 2024 that now permit micro-apartments in all areas designated for multifamily development. This move is part of a broader urban planning strategy to add 120,000 new apartments over the next 20 years, aimed at stemming housing unaffordability.

The ripple effects of these changes are evident not only in new developments but also in existing inventory. San Francisco currently holds the highest share of micro-apartments among its total apartment stock, with 14% of units under 441 square feet. The city’s high population density and competitive rental market have made smaller apartments a viable alternative for many residents. As the report notes, “28% of San Francisco’s new construction pipeline is made up of tiny units,” some of which are as small as 124 square feet—the smallest tracked in the study.

While many of the top 10 cities for micro-apartment construction are in the West, including Reno, San Diego, and Portland, only Philadelphia represents the East Coast in this group. Notably, Seattle also ranks high in terms of existing stock, with 12% of apartments classified as micro-units, trailed by Honolulu at 11.6%.

In contrast, cities in the Mountain West are trending in the opposite direction, favoring significantly larger unit sizes. In places like Gilbert, Arizona, Santa Clarita, California, and Enterprise, Nevada, new apartments are considerably roomier. In Enterprise, the smallest new unit still measures 735 square feet—nearly six times the size of the smallest apartment in San Francisco.

The micro-apartment trend reflects evolving urban lifestyles and shifting priorities, especially among younger renters and single-person households. While some critics raise concerns about livability and space constraints, others point to the potential for these units to expand access to housing in cities where affordability is increasingly out of reach.

With policymakers continuing to prioritize density, climate-conscious urban design, and affordability, micro-apartments are poised to play an even larger role in reshaping America's housing landscape.

Originally reported by Mary Salmonsen in Multifamily Dive.