Living to 100 is uncommon but far less rare than it used to be. In the United States, roughly 80,000 people were centenarians as of the 2020 census, a 50% increase from 53,364 in 2010. Globally, estimates put the number between 575,000 and 700,000 living centenarians. That sounds like a lot, but it’s a tiny fraction of the world’s 8 billion people.
Your Odds of Reaching 100
The chances depend heavily on when you were born. For babies born today, the odds are surprisingly good: about one in three will live to see their 100th birthday, according to projections from the UK’s Office for National Statistics. Broken down by sex, roughly 35% of baby girls and 28% of baby boys born now are expected to reach the century mark.
For people already in middle age or older, the math is different. These projections reflect improvements in medicine, nutrition, and public health that today’s babies will benefit from across their entire lifespan. If you’re currently 50 or 60, your lifetime odds are lower than a newborn’s, though still considerably better than your grandparents’ generation faced.
Why Women Dominate the Numbers
Among centenarians, 85% are women and only 15% are men. At the supercentenarian level (age 110 and beyond), the female share climbs to around 90%. Several biological explanations help account for this gap.
Testosterone, while beneficial for muscle strength and bone density earlier in life, increases the risk of blood clots, heart disease, and stroke at older ages. Women also carry two X chromosomes, giving their cells a backup copy to draw from when one has a disadvantageous variant. Men have just one X chromosome and no alternative. There’s also a theory that evolutionary pressure to protect female fertility selected for genes that slow aging across the entire body, not just the reproductive system.
Paradoxically, the men who do reach 100 tend to be healthier and more functionally independent than their female counterparts. Women appear better at surviving age-related diseases, even if those diseases take a greater toll on daily function. Men who can’t withstand those same conditions simply don’t make it to 100.
Genetics vs. Lifestyle
About 25% of the variation in human lifespan comes from genetics. The remaining 75% is shaped by environment and behavior. But that ratio shifts as you age. For the first seven or eight decades of life, lifestyle choices are the stronger force: eating well, staying physically active, avoiding tobacco, and limiting alcohol. After 80, genetics plays a progressively larger role in determining who keeps going.
This helps explain why certain regions produce centenarians at dramatically higher rates. In so-called Blue Zones (Okinawa, Sardinia, the Nicoya Peninsula in Costa Rica, Ikaria in Greece, and Loma Linda in California), people reach 100 at ten times the rate seen in the rest of the United States. These communities share lifestyle patterns including plant-heavy diets, daily natural movement, strong social networks, and a sense of purpose. The genetics in these populations aren’t radically different. The daily habits are.
What Health at 100 Actually Looks Like
The stereotype of centenarians as universally frail and bedridden doesn’t match the data. A Dutch study of cognitively healthy centenarians found that 52% lived independently, either on their own or in residences where help was available but not required. Only about 2% lived in nursing homes. Eighty percent were independently mobile, 87% had moderate to good hearing, and 77% had moderate to good vision.
Cognitive health was more intact than many people expect. In the same study, 83% of participants were rated as cognitively healthy. About 32% were fully independent in all activities of daily living, like bathing, dressing, and eating, while another 45% needed only minimal assistance. This was a study that specifically recruited cognitively healthy centenarians, so it represents the better end of the spectrum, but it shows that reaching 100 with your mind and body largely intact is possible.
What Centenarians Actually Die From
The causes of death for centenarians look strikingly different from those for people in their 80s. A large English study tracking over 35,000 centenarian deaths found that the single most common cause listed was simply “old age” or frailty, accounting for 28% of death certificates. When included as a contributing factor rather than the primary cause, old age appeared on 76% of centenarian death records.
Pneumonia was the second leading cause at nearly 18%, compared to just 6% for people aged 80 to 84. Cancer, by contrast, caused only 4.4% of centenarian deaths versus about 25% in the younger elderly group. Heart disease dropped from 19% to under 9%. The pattern suggests that people who reach 100 have already survived the diseases that kill most people decades earlier. What ultimately ends their lives is often the gradual wearing down of the body itself rather than a single catastrophic illness.
The Supercentenarian Frontier
If reaching 100 is rare, reaching 110 is almost vanishingly so. Only about 700 supercentenarians are estimated to be alive worldwide at any given time. Researchers have validated just over 3,000 deceased supercentenarians born between 1788 and 1913. Out of every roughly 1,000 centenarians, only one or two will make it another decade.
The Numbers Are Growing Fast
The centenarian population is expanding rapidly. In the U.S., the Census Bureau projects the number will more than quadruple from about 101,000 in 2024 to 422,000 by 2054. Globally, the centenarian population is expected to grow eightfold by 2050, reaching an estimated 3.7 million. These increases reflect both larger birth cohorts aging into their 100s and continued gains in life expectancy at older ages.
Living to 100 is still unusual today, but it’s becoming steadily less so. For children born now, it may be closer to ordinary than exceptional.