Infant Mortality Rate
Definition
The number of deaths of infants under one year of age per 1,000 live births in a given year. It is one of the most sensitive indicators of overall health system quality and population well-being.
Why It Matters
Infant mortality reflects maternal health, access to prenatal care, nutrition, sanitation, and the overall quality of a country's healthcare system. It is used by the WHO and World Bank as a key development indicator.
How It's Measured
Calculated from vital registration data (birth and death certificates). Countries with incomplete vital registration use survey-based estimates.
Current Value
US: approximately 5.4 per 1,000; Japan (lowest): approximately 1.7; Central African Republic (highest): approximately 81
Related Ranking
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Frequently Asked Questions
The number of deaths of infants under one year of age per 1,000 live births in a given year. It is one of the most sensitive indicators of overall health system quality and population well-being.
Infant mortality reflects maternal health, access to prenatal care, nutrition, sanitation, and the overall quality of a country's healthcare system. It is used by the WHO and World Bank as a key development indicator.
Calculated from vital registration data (birth and death certificates). Countries with incomplete vital registration use survey-based estimates.
Infant Mortality Rate is one of the U.S. population demographics concepts that recurs across this site. The definition above is the technical answer; the paragraphs below add the practical context for how the concept connects to the the U.S. Census Bureau ACS and decennial files data behind every per-entity page on the site.
In the the U.S. Census Bureau ACS and decennial files data, this concept shapes one or more of the fields that drive the per-entity grades and rankings on this site. The methodology page describes which fields feed into which output; this glossary entry documents the underlying term.
Source: U.S. Census Bureau ACS, 2026.