The Demographic Outlook: 2026 to 2056

The size of the U.S. population and its composition by age and sex have significant implications for the economy and the federal budget. For example, the number of people at the prime working ages of 25 to 54 affects the number of people who are employed, and the size of the population age 65 or older affects the number of Social Security and Medicare beneficiaries.

In this report, the Congressional Budget Office describes its population projections, which underlie the baseline budget projections and economic forecast that the agency will publish in February 2026. The population projections reflect laws and policies that were in place as of September 30, 2025.

• Population. The Social Security area population is projected to increase from 349 million people this year to 364 million in 2056. (That measure of the population, which is relevant for estimating payroll taxes and benefits for Social Security, includes residents of U.S. states and territories, as well as U.S. citizens, federal employees, and service members living abroad.) The segment of the population age 65 or older is projected to grow more quickly, on average, than younger groups, causing the average age of the population to rise.
• Population Growth. On the basis of recent laws, policies, and demographic trends, CBO projects that the rate of population growth will generally slow over the next 30 years, from an average of 0.3 percent a year in the next decade to an average of 0.1 percent a year from 2037 to 2056. The total population is projected to stop growing in 2056 and remain roughly the same size as in the previous year. Thereafter, the population is projected to shrink. Net immigration (the number of people who migrate to the United States minus the number who leave) is projected to become an increasingly important source of population growth in the coming years, as declining fertility rates cause the annual number of deaths to exceed the annual number of births starting in 2030. Without immigration, the population would begin to shrink in 2030.
• Civilian Noninstitutionalized Population. Some of CBO's economic projections (such as of gross domestic product and the labor force) depend on the number of people age 16 or older who are not on active duty with the armed forces or in institutions. CBO produces two projections of that civilian noninstitutionalized population using differing data from federal agencies. Each projection totals 301 million people in 2056, consistent with CBO's projection of overall population growth.
• Changes Since January and September 2025. CBO typically publishes updated demographic projections early in the calendar year. In 2025, it also released updated projections in September, which reflected laws and policies in place as of July 31. Compared with both of last year's projections, the Social Security area population is now projected to grow more slowly over the next 30 years and to be smaller in 2055 (2.1 percent smaller than projected last January and 0.7 percent smaller than projected last September). Since January 2025, CBO has reduced its projections of fertility rates because of new information and a change in its methods. CBO has also reduced its projections of net immigration from 2025 to 2029 because of administrative actions taken by the current Administration, enactment of the 2025 reconciliation act (Public Law 119-21), and updates to past population data.

CBO's projections of fertility, mortality, and net immigration rates are highly uncertain. Small differences between those projections and actual outcomes could compound over time and significantly alter the demographic picture by the end of the 30-year projection period.