CBO Revises US Population Outlook Downward: Slower Growth, Earlier Negative Natural Increase, Rising Dependency Ratios

The Congressional Budget Office's January 2026 Demographic Outlook projects the US population rising from 349 million in 2026 to 364 million in 2056, a notably slower trajectory than pre-pandemic forecasts. This revision reflects COVID-era excess mortality, persistently low fertility, and recent declines in net immigration. Natural increase (births minus deaths) is expected to turn negative around 2030, after which all net population growth will depend on immigration. The old-age dependency ratio will worsen from 2.7 working-age adults (25-64) per person 65+ in 2026 to 2.2 by 2056 as baby boomers age. These shifts carry direct implications for Social Security, Medicare, and Medicaid financing, as well as labor force participation and long-term economic planning. Independent analysis from the Wharton Budget Model shows a similar slowdown, projecting growth from roughly 343.5 million to 371.5 million over the same period, underscoring that immigration alone cannot fully offset structural demographic headwinds. Earlier Census and CBO baselines anticipated substantially higher totals by mid-century, illustrating how successive downward adjustments have become the norm rather than the exception.