How to Estimate Life Expectancy

What a life table actually is

A life table is a statistical tool built by national statistics offices. For each age, it records the probability of dying within the next year based on recent mortality data, then works out the average number of years a person of that age can expect to live. Insurers and pension planners rely on these tables every day.

The best-known figure is life expectancy at birth, but the table gives a value for every age. Because it is built from an entire population, it describes averages across millions of people — it says nothing certain about any single individual.

Why the number rises as you age

A common surprise is that your expected age at death goes up the older you get. If life expectancy at birth is 80, a 70-year-old is not left with just 10 years. Having already survived the risks of earlier decades, they might expect, on average, another 15 or more years — putting their expected age at death above 85.

This happens because the birth figure averages in everyone who dies young. Once you have passed those early hazards, you are no longer part of that lower group, so your personal outlook improves. This is why a calculator asks for your current age and sex before giving a figure.

Reading the numbers by age and sex

Take a worked example. Suppose a life table shows that a 40-year-old woman has, on average, 45 remaining years. Her estimated age at death is her current age plus that figure: 40 + 45 = 85. A 40-year-old man in the same table might have 41 remaining years, giving an estimate of 81. The gap reflects the well-documented longevity advantage women hold in most countries.

Remember that these are averages for a whole group. Lifestyle, health conditions, income, and where you live all shift an individual's real outlook well above or below the table figure. Use the number as a planning baseline, not a personal countdown.

Frequently asked questions

Is life expectancy a prediction of when I will die?

No. It is a statistical average across a whole population of the same age and sex, not a forecast for you personally. Individual outcomes vary widely around the average.

Why do women tend to live longer than men?

The gap comes from a mix of biological and behavioral factors, including differences in heart-disease risk, hormones, and historically higher rates of smoking and occupational hazards among men. In most countries women outlive men by several years.

How can life expectancy be higher than at birth once I am older?

Because the birth figure includes everyone who dies young. Once you have survived those early risks, your expected age at death rises — a 65-year-old typically has an estimate several years above the birth-based number.

What data are life expectancy figures based on?

They come from official mortality statistics — recorded deaths by age and sex — published by national statistics offices and bodies such as the WHO. The tables are updated regularly as new data arrive.