The global average life expectancy is 73 years, based on 2024 World Bank data. That single number, though, masks enormous variation depending on where you live, your sex, your income, and how you take care of your body. In the United States, life expectancy just hit a record high of 79 years in 2024. Here’s what shapes those numbers and what they actually mean for you.
How Life Expectancy Has Changed Over Time
In 1900, the average newborn could expect to live just 32 years. By 2021, that figure had more than doubled to 71 years, and it has continued climbing since. The gains came from cleaner water, vaccines, antibiotics, better nutrition, and dramatic reductions in infant and childhood mortality. Record life expectancy has risen at a remarkably steady pace: roughly one additional year for every four calendar years.
That trajectory isn’t perfectly smooth. The COVID-19 pandemic knocked U.S. life expectancy down to 76.4 years in 2021, erasing nearly two decades of progress in a single year. But the rebound has been swift. U.S. life expectancy climbed to 78.4 in 2023 and then to 79 in 2024, its highest level ever recorded. A major reason for that latest jump: drug overdose death rates fell 26.2% between 2023 and 2024, the largest single-year decline on record. Synthetic opioid deaths specifically dropped 35.6%.
Why Women Live Longer Than Men
Women outlive men in virtually every country on Earth. Globally, the gap runs about four to five years. The reasons are partly biological and partly behavioral. Men are far more likely to die from preventable causes like heart disease, lung cancer, and traffic accidents. A WHO analysis found that when facing the same disease, men seek healthcare less often than women.
For women, the picture has its own risks. Breast cancer, complications of pregnancy, cervical cancer, and Alzheimer’s disease are the conditions that most reduce female life expectancy relative to men. In low-income countries where women lack access to maternal healthcare, the gap between male and female life expectancy narrows, not because men live longer but because more women die in childbirth.
The Income Gap Is Striking
Few factors predict how long you’ll live as reliably as income. In the United States, the gap in life expectancy between the richest 1% and the poorest 1% is roughly 15 years for men and 10 years for women. To put concrete numbers on it: a 40-year-old man in the bottom 1% of earners can expect to live to about 73, while his counterpart in the top 1% can expect to reach 87. For women, the figures are 79 and 89, respectively.
That gap is not static. It widened between 2001 and 2014, meaning the wealthiest Americans pulled further ahead while the poorest saw smaller gains. Higher income correlates with better access to healthcare, healthier food, safer neighborhoods, less chronic stress, and lower rates of smoking and substance use. These advantages compound over a lifetime.
What Determines Your Individual Lifespan
Genetics plays a real but modest role. Researchers estimate that about 20% to 25% of the variation in human lifespan comes from inherited genes. Some of the gene variants linked to longevity are involved in DNA repair, maintenance of telomeres (the protective caps on the ends of chromosomes that shorten with age), and defense against free radicals, unstable molecules that damage cells over time. Other longevity-linked genes influence cholesterol levels, inflammation, and immune function, reducing the risk of heart disease, which remains the leading killer of older adults.
That leaves roughly 75% to 80% of the variation down to environment, behavior, and luck. The biggest lifestyle factors that shorten life are smoking, physical inactivity, heavy alcohol use, poor diet, and obesity. Heart disease is still the number one cause of death in the U.S., followed by cancer and unintentional injuries. Regular physical activity, maintaining a healthy weight, not smoking, and moderate alcohol intake are consistently linked to adding years, sometimes a decade or more, compared to people with none of those habits.
Life Expectancy Once You Reach 65
The headline number of 73 or 79 years is calculated at birth, which means it factors in every death at every age, including infant mortality and deaths among young adults. If you’ve already made it to 65, your remaining life expectancy is considerably longer than the birth figure suggests. In the U.S., a 65-year-old man can expect about 18 more years (to age 83), and a 65-year-old woman about 20.5 more years (to around 85.5). Each year you survive effectively recalculates your odds upward, because you’ve already avoided the risks that kill people younger.
This is why financial planners and retirement researchers use “conditional life expectancy” rather than the headline number. If you’re planning for retirement at 65, planning around the average birth life expectancy of 79 could leave you short by several years.
Where Life Expectancy Varies Most
The global average of 73 years sits between extremes. Japan, Switzerland, Singapore, and several other high-income countries have life expectancies above 83 years. Parts of sub-Saharan Africa still fall below 60, dragged down by infectious diseases, limited healthcare infrastructure, and higher maternal and infant mortality. The gap between the longest-lived and shortest-lived countries is more than 25 years.
Within the United States, geography matters too. Life expectancy varies by more than 20 years between the healthiest and least healthy counties, driven by differences in poverty rates, access to medical care, diet, smoking prevalence, and environmental exposures. Your zip code, in many cases, is a stronger predictor of your lifespan than your genetic code.