Recorded 1880–2025 · United States
Rex was most popular in 1952, when 1,505 American babies were given the name — ranking #373 that year. In 2025 it ranked #1,769, with 281 births. Across 1880–2025 the Social Security Administration has recorded 60,590 people named Rex.
The Social Security Administration’s records begin in 1880, and Rex is already there in that first year — so the name is older than the record and these figures cannot date it. It has been recorded in 146 of the 146 years since.
The Social Security Administration has recorded 60,590 American births named Rex between 1880 and 2025. That is recorded US births, not a world population — it counts people issued a Social Security number at birth in the United States. Of those, roughly 35,828 are estimated to be alive today.
281 American babies were named Rex in 2025, ranking #1,769 that year.
Rex is holding steady. Across 2021–2025 it averaged 346 births a year, against 385 a year across 2011–2015 — a change of -10% over the decade.
Measured on recorded births. American births overall have fallen since 2007, so most established names lose births over any recent decade — a name can shed births and still hold its rank. Compare the rank above, which is measured against the other names of the same year.
Across the whole record Rex is a boy’s name — 0.2% of the 60,590 Americans given it were girls and 99.8% were boys. In births since 2016 it is 0% girls and 100% boys.
Counted from every US birth the Social Security Administration recorded under this name, so it reflects use rather than opinion. A name given to fewer than five babies of one sex in a year is withheld at source and is not counted.
Roughly 35,828 Americans named Rex are alive today — 59% of everyone ever recorded with the name. The median is 62 years old, and half are between 33 and 71. That is a wide band, the mark of a name in steady use across generations rather than a passing fashion.
An estimate, not a count. Recorded births are carried forward through the Social Security Administration’s 2023 period life table, by age and sex. That table describes mortality in one recent year, so it credits the oldest cohorts with today’s survival rather than the harsher rates they actually lived through — the further back a name peaked, the more this will overstate how many remain. It counts people issued a Social Security number at birth, not immigrants who arrived later.
How much more common the name is in each state than across the country as a whole.
See Rex on the interactive charts
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Source: U.S.A. Social Security Administration. Years 1880–2025. namelegacy.org