What life expectancy at birth means and how it is measured
Life expectancy at birth in the United States is the average number of years a newborn is expected to live if current mortality rates hold through their lifetime. It is not a prediction for any individual, but a population summary based on age-specific death rates in a given year. In the US, life expectancy at birth has declined slightly in recent years after decades of slow improvement, reflecting shifts driven by disease outbreaks, drug overdoses, and unequal access to care. It is typically summarized as an overall figure, yet it varies substantially by sex, race, geography, and socioeconomic circumstances.
Because life expectancy at birth depends on the entire age-specific death schedule, it is sensitive to changes in mortality at younger and older ages differently. Increases in deaths among working-age adults, for example, can depress life expectancy more than the same number of deaths concentrated at much older ages. Analysts use life expectancy at birth to compare population health over time and across countries, while recognizing that causes of death and the population mix evolve. The following sections explain how the measure is constructed, how it is reported, and how patterns differ across subgroups and places in the US.
Key definitions and calculation basics
- Life expectancy at birth: the average number of years a person would live if they experienced the age-specific death rates of a given year from birth onward.
- Period measure: calculated from deaths in a single year applied to a midyear population; reflects past and present mortality but not future medical or social changes.
- Complete cohort vs abridged methods: the US official life tables use an abridged approach, grouping ages to simplify estimation without material loss of accuracy for policy use.
How the US calculates and reports life expectancy at birth
The National Center for Health Statistics (NCHS), part of the Centers for Disease Control and Prevention, produces annual life tables using death counts from the National Vital Statistics System and population estimates from the Census Bureau. Each year’s life table begins with the exact number of deaths by single year of age (or single year for younger ages, then grouped) and applies these rates to a hypothetical cohort of 100,000 live births. The table then tracks how many survivors remain at each age, summing the expected years lived to derive life expectancy at birth. Key steps include adjusting for underreporting and misreporting, updating population denominators, and revising past years when revised data are published. Because it is a period measure, the reported value reflects the mortality patterns of the year, not necessarily the life span that newborns will actually reach.
Data sources and methods used by NCHS
- National Vital Statistics System: death certificates filed in all states and the District of Columbia, coded using ICD-10/10th revision rules.
- Population denominators: Census Bureau population estimates by age, sex, race, and Hispanic origin.
- Life table method: exact years lived method for age one and older; Lenart adjustment for infant life expectancy to reduce bias from neonatal reporting differences.
The result is the official period life expectancy at birth published by CDC/NCHS. It is widely used for international comparisons, monitoring trends, and informing public health planning, though it does not account for future changes in risk factors, medical technology, or policy that could alter mortality trajectories.
Recent trends and context for the United States
US life expectancy at birth declined from 2019 to 2021, driven largely by the COVID-19 pandemic, increases in drug overdose deaths, and rises in homicide and other external causes. Between 2019 and 2023, provisional estimates show a modest rebound, but the level remains below pre-pandemic peaks. Much of the earlier stagnation and decline was concentrated among younger and middle-aged adults, widening disparities by age, race, ethnicity, and place. While improvements have occurred at the oldest ages, progress at younger ages has been uneven, leading to slower gains in overall life expectancy at birth than in many peer nations. Continued monitoring is required to determine whether recent rebounds represent sustained improvements or temporary fluctuations.
Comparison with recent years (illustrative; verify with latest NCHS tables)
| Period | US Life Expectancy at Birth (years) | Notes |
|---|---|---|
| 2019 | 78.86 | Pre-pandemic high in recent cycle, subject to later revision. |
| 2020 | 77.28 | Sharp decline associated with COVID-19 and drug overdose increases. |
| 2021 | 76.60 | Low point in this period, driven by external causes and inequities. |
| 2022 | 77.55 | Preliminary upward movement, some causes reduced, others persist. |
| 2023 | 77.56 | Provisional; slight gain, still below 2019 level; subject to final revision. |
Notes: Values above are rounded to two decimals and reflect the latest provisional or finalized NCHS reports available through 2023. Annual revisions can change past years by small amounts, and future reports may adjust 2022–2023 as complete data and methodology updates are finalized. Differences by age, sex, and race are substantial and described below.
Disparities by demographic and geographic factors
Life expectancy at birth in the US differs markedly by sex, race, ethnicity, and geography. Females consistently live longer than males, and these gaps persist even as both trends move in the same direction. Black and Hispanic populations have historically experienced lower life expectancy at birth than non-Hispanic White people, though reductions in some inequities have occurred in recent decades. Place matters substantially: people in some states and counties have life expectancies several years above the national average, while others lag behind, reflecting differences in health care access, economic opportunity, public health infrastructure, and social determinants. These differences mean the national average can mask large variations for subgroups and regions that experience much higher or lower risks.
Illustrative differences by sex and race (typical ranges; verify with current year detail)
- Sex: Females generally live 5 to 8 years longer than males at birth, with the gap narrowing slowly over time.
- Race and ethnicity: Non-Hispanic Black populations have exhibited the lowest life expectancy at birth in recent cycles, followed by non-Hispanic White and other groups, with Hispanic populations often showing a mortality advantage (Hispanic paradox) in some periods despite socioeconomic disadvantages.
- Geography: States in the South and regions with higher poverty, opioid overdose, and homicide rates tend to have lower life expectancy at birth; states with stronger health systems and social supports tend to rank higher.
How life expectancy at birth differs from other survival measures
Life expectancy at birth is a period measure that blends risks across ages, whereas life expectancy at age 65 or older reflects survival after surviving early mortality. Life expectancy at birth is highly sensitive to infant and child mortality, which are small in the US but vary by race and place. If infant mortality were eliminated, life expectancy at birth would rise, but gains among older adults would still shape overall trends. Life table methods allow analysts to compare period life expectancy with more forward-looking cohort expectations by applying different future mortality assumptions, but the published national number is a period estimate, not a forecast for babies born today.
Comparison of life expectancy metrics at a glance
| Metric | What it measures | Why it matters |
|---|---|---|
| Life expectancy at birth (period) | Average years lived if a newborn experienced a given year’s age-specific death rates. | Standard summary of population health and comparator across time and place. |
| Life expectancy at age 65 | Average remaining years for people who have already reached 65. | Relevant for retirement, Medicare, and long-term care planning. |
| Period vs cohort life expectancy | Period uses one year’s rates; cohort projects future rates under alternative assumptions. | Period comparisons are standardized; cohort expectations inform long-term policy. |
Limitations and how to interpret life expectancy at birth
Life expectancy at birth is sensitive to the age pattern of mortality in the reference year and to fluctuations from causes that are rare but impactful, such as pandemics or drug overdose epidemics. It is not a guarantee or a budget for how long an individual will live; a child born in a high-mortality year could live much longer if future conditions improve. Because it is a period measure, it can move in counterintuitive ways when mortality shifts across ages: for example, a large reduction in deaths at older ages can yield smaller gains in life expectancy at birth than the same reduction concentrated among younger adults. When interpreting year-to-year changes, consider whether they reflect sustained trends or transient shocks, and compare subgroups and ages instead of relying on a single national number.
Reliable sources for US life expectancy at birth
For current and historical US life expectancy at birth, consult the National Center for Health Statistics (NCHS) life tables and accompanying reports, the CDC Wonder database, and publications from the National Academies of Sciences, Engineering, and Medicine. International comparisons can be drawn from the World Health Organization and the World Bank, though definitions and methods differ. When using data, note whether values are final, preliminary, or revised, and whether they refer to the period life expectancy at birth or alternative survival measures. For research or policy, examine trends alongside cause-of-death data, mortality risk by age, and social determinants to build a fuller picture of population health.
Quick takeaways
- Life expectancy at birth is a period average of current mortality rates, not a forecast for individuals.
- In the US, it rose slowly for much of the 20th century, stalled in the late 2010s, declined 2019–2021, and has shown modest recovery since, but remains below pre-pandemic levels.
- Disparities by sex, race, ethnicity, and geography are large and persistent, with lower life expectancy at birth among Black populations and in regions with concentrated socioeconomic disadvantage.
- Because it is sensitive to deaths at younger ages, changes in drug overdoses, homicides, and external causes can move the national figure more than the same number of deaths at older ages.
- Use period life expectancy at birth to compare US population health across time and with other countries, but complement it with age-specific measures and cohort projections for planning and context.