How Long You Live Depends on Where You're Born

Three mechanisms account for most of the spread. Rich countries spend roughly sixty times as much per person on healthcare as the poorest ones, and that gap in spending tracks closely with how many children survive past their fifth birthday. Falling child and maternal mortality drove most of the world's life-expectancy gains over the past century, and where those rates stay high, they still pull the birth-cohort average down hard. Conflict compounds both effects: a regression analysis of health data from 181 countries between 2000 and 2019 found that armed conflict is linked to sustained increases in under-five mortality for three to five years afterward, and in maternal mortality for up to seven. All ten of the lowest-ranked countries in this dataset are in Sub-Saharan Africa, a region where low health spending, high child mortality and active conflict often overlap.

That mechanism shows up starkly in the raw child-mortality numbers behind this ranking. The World Health Organization puts Sub-Saharan Africa's under-five mortality rate at 71.6 deaths per 1,000 live births in 2024, against a global average of 37.4 — the highest of any region, and nearly fourteen times the rate in Europe and Northern America. A statistic built from life expectancy at birth is mechanically sensitive to exactly this kind of gap: a region that loses roughly one in fourteen children before age five will show a lower cohort average than one that loses a fraction of that, even before any difference in adult mortality is counted.

Monaco is an outlier in more than life expectancy. The country covers under two square kilometers, has roughly 36,000 residents, and runs an economy built on banking, real estate and tourism for the wealthy — nothing like the profile of Nigeria's more than 200 million people, or of most of the 217 countries in between. Treating its 86.5-year figure as the ceiling of the entire ranking risks explaining a genuinely global pattern with one small nation's circumstances.

Averaging across full cohorts removes that risk. The ten highest-ranked countries in this dataset — Monaco, San Marino, Hong Kong SAR, Kuwait, Switzerland, Andorra, French Polynesia, Liechtenstein, Sweden and Italy — average 84.7 years. The ten lowest — Nigeria, Chad, Central African Republic, South Sudan, Lesotho, Somalia, Mali, Guinea, Benin and Burkina Faso — average 58.6 years. The difference is 26.1 years, nearly as wide as the 31.9-year gap between the two single extremes, and it survives the objection that either end of the table is a statistical fluke. The top-ten boundary itself splits a tie: Italy and Japan both post 84.0 years, and only the dataset's ordering, not a meaningful health difference, puts one at tenth and the other at eleventh.

Sorting all 217 countries into the seven regions the World Bank uses for its own reporting shows the same pattern at a coarser grain. North America's median life expectancy is 82.1 years, though the region has only three countries in this dataset: the United States, Canada and Bermuda. Europe & Central Asia, with 58 countries, sits at 79.9. The Middle East, North Africa, Afghanistan & Pakistan grouping, 23 countries, is next at 76.7, followed by Latin America & the Caribbean, 42 countries, at 75.7, South Asia, 6 countries, at 74.1, and East Asia & Pacific, 37 countries, at 73.0. Sub-Saharan Africa, the largest single region in the dataset at 48 countries, has by far the lowest median: 64.3 years.

That regional floor sits below almost every individual country ranked above it. Sub-Saharan Africa's 64.3-year median is lower than all 53 countries in the dataset that reach 80 years or higher — the lowest of that group, Czechia, still posts 80.0. Within the region itself, only two of its 48 countries clear 75 years: Seychelles, the regional high point at 76.3, and Cabo Verde at 76.2. The distance between the best-performing region, North America at 82.1, and the worst, Sub-Saharan Africa at 64.3, is 17.8 years — a gap wide enough to separate entire continents' worth of people, not just two individual countries.

The Monaco-Nigeria comparison sits at the extreme tails of a much larger distribution, and the tails are thin. Only three of the 217 countries in this dataset reach 85 years or higher: Monaco at 86.5, San Marino at 85.8 and Hong Kong SAR at 85.4. Expand the threshold to 80 years and the count rises to 53 countries, roughly 24% of the field. At 75 years it is 106 countries, just under half. At 70 years it is 153, or 71% of every country and territory the World Bank tracks — meaning most of the world's population lives somewhere with a life expectancy most people would consider reasonably long.

The bottom of the distribution is smaller still. Only six countries in the entire dataset fall below 60 years, and every one of them — Nigeria, Chad, Central African Republic, South Sudan, Lesotho and Somalia — is in Sub-Saharan Africa. That six-country cluster, not the wider 217-country field, is what actually explains why the region's overall median sits so far below the rest of the world: a small number of countries with severe, compounding mortality pressures pull a regional average down much further than a broad, even distribution ever could.

Life expectancy at birth is a period average across everyone born in a given year, weighted heavily by deaths in infancy and early childhood — which is why the figure can swing far faster than intuition about aging suggests. Nigeria's 54.6 years is not the age most Nigerians die at; someone who survives childhood already has a meaningfully higher expected age, the same pattern documented globally for how life expectancy calculated from an older starting age runs well above the birth-year figure. The birth-cohort number is the right tool for comparing population health across countries. It is the wrong one for guessing how long any individual adult will live.

This is not a quirk specific to Nigeria's data. Demographic researchers have long noted that in any population with a high concentration of deaths in infancy and early childhood, life expectancy at birth can sit well below the age most people who survive that window actually go on to reach — one widely cited illustration holds that a society with a birth-year life expectancy of just 30 can still see a person who survives to age five expect another 40 years of life, because the low average is driven almost entirely by deaths concentrated at the very start of life rather than spread evenly across every age. Nigeria's 54.6-year figure works the same way: a low starting number produced disproportionately by mortality in the first years of life, not evidence of a compressed adult lifespan.