Life expectancy is an average, not a forecast
This page carries the figures used by the rest of this family of calculators, says who published each one and for which year, and explains what a life expectancy figure does and does not describe. The short version: it describes a population in a single year. It is not a statement about any individual, and no tool, including ours, can turn it into one.
What does life expectancy at birth actually mean?
A period life table takes the death rates observed at every age during one calendar year and applies all of them at once to an imaginary cohort of newborns. Life expectancy at birth is the average age at death of that imaginary cohort. Nobody actually lives through those conditions, because the death rates a real person meets at seventy will be the rates of a year seventy years away, not this year's. The figure is a summary of present-day mortality expressed in years, which is a useful and comparable thing to have, and a different thing from a forecast.
This is also why the number moves. United States life expectancy at birth was 76.4 years for 2021 and 77.5 years for 2022 on the same NCHS series. Nobody's life changed length in between. The death rates observed in the reference year changed, and the summary moved with them.
Life expectancy figures and where they come from
These are the only figures used anywhere in this family of pages. Each one is a period life expectancy at birth, and each carries the body that published it and the year it refers to. Where a figure could not be verified it was left out rather than estimated, which is why this table is short.
| Population | Years | Weeks | Reference year | Published by |
|---|---|---|---|---|
| United States, everyone | 77.5 | 4,044 | 2022 | NCHS |
| United States, male | 74.8 | 3,903 | 2022 | NCHS |
| United States, female | 80.2 | 4,185 | 2022 | NCHS |
| United States, everyone | 76.4 | 3,986 | 2021 | NCHS |
| United States, male | 73.5 | 3,835 | 2021 | NCHS |
| United States, female | 79.3 | 4,138 | 2021 | NCHS |
| United Kingdom, male | 78.6 | 4,101 | 2020 to 2022 | ONS |
| United Kingdom, female | 82.6 | 4,310 | 2020 to 2022 | ONS |
| World average | 71.4 | 3,725 | 2021 | WHO |
| World average | 73.1 | 3,814 | 2019 | WHO |
National Center for Health Statistics (NCHS), United States
The NCHS publishes United States period life tables each year as part of the National Vital Statistics System. The United States figures above are life expectancy at birth for the reference years 2021 and 2022, split by sex and combined. The NCHS series is the one most American reporting on the subject quotes, and the Social Security Administration publishes its own period life table on a similar basis for actuarial use.
Office for National Statistics (ONS), United Kingdom
ONS national life tables are published as a three-year average, which smooths out single-year fluctuations. The figures above are from the National life tables: UK release covering 2020 to 2022, giving 78.6 years for males and 82.6 years for females at birth. Because the release is a three-year average, a single unusual year affects it less than it affects an annual series.
World Health Organization (WHO), world
The WHO global figure averages every country in the world, weighted by population, so it sits well below the figure for any high-income country. Global life expectancy at birth was 73.1 years for 2019 and 71.4 years for 2021. The fall between those two reference years is the clearest illustration available of what a period figure is measuring: a change in observed mortality in a particular year, summarised as years.
Why is life expectancy not a personal prediction?
Three reasons, and any one of them is sufficient. First, an average describes a distribution, and a distribution has a spread; the average tells you nothing about where in the spread a given person sits. Second, a period figure holds today's death rates fixed across an entire lifetime, which is a deliberate simplification rather than a claim about the future. Third, the figure is computed for a population defined by country and year, and no individual is a population.
The practical consequence is that a sentence like "you will live until" cannot be produced from this data, and any page that produces one is not doing arithmetic. The honest version is the one used throughout this site: on average, someone in a given population lives about so many years, and here is how many weeks that is.
What is the difference between life expectancy at birth and remaining life expectancy?
One thing worth knowing about the arithmetic: subtracting the time you have already lived from life expectancy at birth is not the same as remaining life expectancy. Life expectancy at birth includes everyone who died young. Anyone who has already reached a given age has, on average, longer left than the subtraction suggests, and the gap widens with age. Published life tables carry a separate remaining-life column for exactly this reason. We do not hold those values, so this page does the plain subtraction and tells you what it is.
Concretely: if life expectancy at birth in some population is 77.5 years, a sixty year old in that population does not on average have 17.5 years left. They have more, because they have already passed through every age at which they might have died young, and the average at birth was dragged down by people who did not. The published life tables have a column for this. Ours do not, so we do not claim it.
Does life expectancy tell me anything useful at all?
Yes, as a unit of scale. If you want to know roughly how many weeks fit into a long life so that a week has a context, a published average is the right input and the precision of the last decimal is irrelevant. That is exactly what the life in weeks grid uses it for. It is the wrong input for any question about a specific person, and we do not use it for one.
Questions
- What is life expectancy at birth?
- The average age at death of an imaginary cohort that experiences, at every age, the death rates observed in one calendar year. It summarises a population in that year.
- What is life expectancy in the United States?
- 77.5 years at birth for the reference year 2022, on the NCHS National Vital Statistics System series, compared with 76.4 years for 2021.
- What is life expectancy in the United Kingdom?
- 78.6 years for males and 82.6 years for females at birth, from the ONS national life tables covering 2020 to 2022.
- What is global life expectancy?
- 71.4 years at birth for 2021 according to the WHO, down from 73.1 years for 2019.
- Can life expectancy predict how long I will live?
- No. It is an average across a population in a single year, and it says nothing about where any individual falls within that population.
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