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Boys' name · 66,778 recorded births

Rex

#859 in the US in 2025

Where Rex stands

United States register · 1880–2025

#859boys’ names · US 2025

Rex was the 859th most registered boys' name in the United States in 2025, on 281 births.

peak 1951 · 1,503188019532025

Its moment was 1951, when 1,503 babies were given it.

SOURCE·US Social Security Administration, national baby-name data·Public domain. retrieved from the Internet Archive's 2026 snapshot of ssa.gov (ssa.gov refuses automated requests); files unmodified. SSA lists a name only if it was given to at least 5 babies of that sex that year.·REVIEWED JUL 2026

#859US rank, 2025 (boys)
281US births in 2025
#170its best US rank, in 1951
1951peak year — 1,503 births
60,449US births since 1880
4,185NZ births since 1909
2,144E&W births, 2019–2025
Saved in this browser only — no account, nothing sent anywhere.

How Rex's figures are worked out

  1. Counts come straight from the registrars: the US Social Security Administration (1880–2025) and the New Zealand Department of Internal Affairs (1900–2025). Nothing is scraped from another names site. The SSA files are the agency's own, retrieved from the Internet Archive's 2026 snapshot of ssa.gov (ssa.gov refuses automated requests); files unmodified.
  2. Ranks are computed against every name in that year's file, not just the ones this site publishes pages for — otherwise a rank would flatter every name we happen to list.
  3. The curve is drawn on births per 100,000 of that sex, not raw counts. Raw counts across eras are misleading: far more births were registered in 1957 than in 1890, so a flat count is a falling share.
  4. The reporting floor. Each registrar publishes a name only once it clears a threshold — 5 births of that sex in the US, 10 in New Zealand. Expressed as a share that threshold is itself a curve, and it is drawn on every chart here as the shaded band along the base.
  5. A missing year is a suppressed value, never a zero. Where the registrar published nothing, this site prints “below floor” or “<5”, the curve is broken rather than drawn across the gap, and the missing years are marked on the floor line. Rex was under the floor in no year of its US record.
share per 100,000 = births ÷ all births of that sex that year × 100,000
reporting floor (share) = 5 ÷ all births of that sex that year × 100,000

Full methodology →

Rex in the United States

188019001920194019601980200020200.04080
Births per 100,000 of that sex, so eras compare fairly. The shaded band is the 5-birth reporting floor — under it the registrar publishes nothing, so a line that stops has left the record, not fallen to zero. Rex in the United States, 1880–2025

Between 2016 and 2025 the name has been falling — down 26% as a share of boys' births.

SOURCE·US Social Security Administration, national baby-name data·Public domain. retrieved from the Internet Archive's 2026 snapshot of ssa.gov (ssa.gov refuses automated requests); files unmodified. SSA lists a name only if it was given to at least 5 babies of that sex that year.·REVIEWED JUL 2026

Rex in New Zealand

In New Zealand, Rex has been registered 4,185 times since 1909, peaking in 1950 with 110 births. It ranked #395 for boys in 2025 on 11 births.

1900192019401960198020002020NOT PUBLISHED — BELOW THE 10-BIRTH FLOOR0.0391782
Births per 100,000 of that sex, so eras compare fairly. The shaded band is the 10-birth reporting floor — under it the registrar publishes nothing, so a line that stops has left the record, not fallen to zero. Rex in New Zealand, 1900–2025

SOURCE·NZ Department of Internal Affairs, births by first name·CC BY 4.0. DIA lists a name only if it was given to at least 10 babies of that sex that year.·REVIEWED JUL 2026

Rex in England & Wales

In England and Wales, Rex was registered 2,144 times between 2019 and 2025, peaking in 2021 with 396 births. It ranked #228 for boys in 2025 on 217 births. Across those years it has been falling.

20200.068136
Births per 100,000 of that sex, so eras compare fairly. The shaded band is the 3-birth reporting floor — under it the registrar publishes nothing, so a line that stops has left the record, not fallen to zero. Rex in England and Wales, 2019–2025

Seven years is a window, not a history. Unlike the American and New Zealand series this one cannot show you a name's arrival or its long decline — ONS publishes the full list only from 2019. England and Wales only: Scotland and Northern Ireland publish separately and are not counted here.

SOURCE·Office for National Statistics, baby names in England and Wales·Open Government Licence v3.0. ONS redacts any name given to 2 or fewer babies of that sex that year, under s40 of the Freedom of Information Act.·REVIEWED JUL 2026

Decade by decade in the US

US rank and births at each decade markSSA · JUL 2026
YearRankBirths
1880#50513
1890#31630
1900#26759
1910#30465
1920#209614
1930#234540
1940#227547
1950#1961,069
1960#2141,314
1970#362507
1980#488300
1990#662232
2000#1,208112
2010#703332
2020#681377

<5 = the SSA published no figure for that year. It is a suppressed value, not a zero.

Where in the United States

The states that registered Rex most often since 1880. These are lifetime totals, so they track state population as much as local taste — a name common in Wyoming will never out-count California.

StateBirths
California4,513
Texas4,445
Indiana3,935
Ohio3,215
Michigan2,887
Illinois2,484
Missouri2,178
Kansas2,022
Iowa2,013
North Carolina1,870

Questions about Rex

How popular is the name Rex?

Rex ranked #859 for boys in the United States in 2025, on 281 births registered with the Social Security Administration.

When was Rex most popular?

Rex peaked in 1951, when 1,503 babies in the United States were given the name.

Is Rex rising or falling?

Measured as a share of all boys' births, Rex has been falling between 2016 and 2025 (-26%).

Same sex, peaking within a few years of 1951, at a comparable scale. Not a taste engine — this is arithmetic on peak years, which is why it will occasionally hand you something unfashionable that is nonetheless exactly of the period.

SOURCE·US SSA (1880–2025) + NZ DIA (1900–2025) birth registrations·ranks and shares computed from the source files, see method·REVIEWED JUL 2026

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Published by

Amit Sharma

Auckland real-estate agent and marketer. Builds free, sourced data tools.