Richer countries live longer, up to a point
Each doubling of income buys fewer extra years of life. The curve economists call the Preston curve.
Countries with higher GDP per Person at PPP tend to have higher Life Expectancy at Birth.
Very strong link: a correlation of 0.86 across 184 countries.CorrelationHow closely two metrics move together, from −1 to +1. Near +1: both rise together. Near −1: one rises as the other falls. Near 0: no clear link.More in the glossary →
In 1975 the demographer Samuel Preston described this curve: life expectancy rises steeply with income in poorer countries, then flattens. Plotting income on a log scale, where each step is a doubling, turns the curve into a near straight line.
Each dot in the chart is one of 184 countries. The correlation between GDP per Person at PPP (on a log scale) and Life Expectancy at Birth is 0.86, a very strong relationship: about 74% of the differences in Life Expectancy at Birth from place to place line up with GDP per Person at PPP. Ranked instead of measured, the link is 0.88.
The highest Life Expectancy at Birth is in Hong Kong (85.4), Kuwait (84.6) and Switzerland (84.4); the lowest is in Nigeria (54.6), Chad (55.2) and Central African Republic (57.7). The median place has 73.8 for Life Expectancy at Birth and $20,451 for GDP per Person at PPP.
The biggest exceptions sit furthest from the trend line. Solomon Islands, Jordan and Malawi have a much higher Life Expectancy at Birth than their GDP per Person at PPP would predict, while Nigeria, Guyana and Nauru have a much lower one.
This is a comparison across places, not proof that one causes the other: both can follow from something else, such as income, age or how urban a place is. GDP per Person at PPP is from 2025 and Life Expectancy at Birth from 2024.
Highest Life Expectancy at Birth
| Place | Life Expectancy at Birth | GDP per Person at PPP |
|---|---|---|
| Hong Kong | 85.4 | $80,423 |
| Kuwait | 84.6 | $56,468 |
| Switzerland | 84.4 | $102,513 |
| Andorra | 84.2 | $79,567 |
| Sweden | 84.1 | $72,529 |
Lowest Life Expectancy at Birth
| Place | Life Expectancy at Birth | GDP per Person at PPP |
|---|---|---|
| Nigeria | 54.6 | $9,532 |
| Chad | 55.2 | $2,903 |
| Central African Republic | 57.7 | $1,314 |
| Lesotho | 57.8 | $3,184 |
| Somalia | 59.0 | $1,643 |
Explore it yourself
- Open this comparison in the interactive chart to highlight places, change the metrics or colour by party.
- Full ranking and sources for GDP per Person at PPP
- Full ranking and sources for Life Expectancy at Birth