Why does life expectancy go up as you get older?
On this page
Because every year you live takes away the chance of dying at that age. The average at birth includes everyone who dies young. An American woman who has reached 65 can expect to reach about 86, not 81, and one who has reached 80 can expect about 90.
What we’d do
Once you’re an adult, ignore the number at birth and use the one for your exact age. Then plan for the odds of reaching 90, because a third of 65-year-old women and a quarter of 65-year-old men get there, and you’ll want those years to be strong ones.
Why it sounds wrong
People hear “life expectancy is 79” and think of it as a finish line that everyone is walking toward, so it seems strange that a 75-year-old woman can expect to reach 88, well past the line. The confusion comes from treating an average across everyone born as if it were a personal deadline.
The simple version
If you’re a senior in high school, your chance of dropping out in 9th grade is zero, since you’re already past it. Your odds of graduating are higher than the odds for the whole class that started 9th grade together. Life expectancy works the same way, one birthday at a time.
How the life table works
The US life table is a list of 101 rows, one for each age from 0 to 100 and over. Each row holds the chance that someone that age dies in the next year, using 2024’s death rates. To get the average age reached from any row, you follow a group of people forward from that age, year by year, and see when they die.
Start the group at birth and the average comes out at 81.4 for women and 76.5 for men. Start it at 65, and the deaths that happen before 65 aren’t in it anymore, so the average comes out higher.
| Age now | Women reach about | Men reach about |
|---|---|---|
| Birth | 81.4 | 76.5 |
| 30 | 82.4 | 78.1 |
| 50 | 83.7 | 80.3 |
| 65 | 85.8 | 83.4 |
| 80 | 89.9 | 88.6 |
| 90 | 94.9 | 94.2 |
The rise is slow at first, because few people die between 30 and 50. It speeds up after 65, when each year you pass removes more of the deaths ahead of you.
Two surprises in the table
The odds of reaching 80 climb fast as you get closer. Of women born today, about 66 in 100 would reach 80 at 2024’s rates. Of women already 65, it’s about 75 in 100, and of women already 70, about 79 in 100.
The gap between men and women nearly closes in very old age. At birth it’s 4.9 years. At 90, it’s less than a year, with women of 90 reaching about 95 on average and men about 94.
What the table can’t know
The table uses one year’s death rates for every age, so it doesn’t guess at medical progress, and it treats every 65-year-old the same. Your habits, fitness and health move your own number around that average, sometimes by years. The calculator starts from the same table and adjusts for five habits, and every age from 50 to 85 has its own page, like 65.
