Rex
A masculine Latin name meaning "king" or "ruler".
Name Census estimates that about 37,623 living Americans carry the first name Rex. The name is used almost exclusively for boys. The average person named Rex today is around 54 years old, and the year with the single highest number of Rex births was 1952 (1,505 babies).
This page is the full Name Census profile for Rex. Below you will find a gender breakdown showing how the name splits between male and female registrations, a year-by-year popularity chart stretching back to 1880, decade-level totals, the top US states for this name, its meaning and etymology, and a set of frequently asked questions with data-backed answers.
For a British comparison, Name Census UK has a UK baby-name profile for Rex with official rankings and popularity over time.
Key insights
- • Although Rex is used almost entirely for boys, the SSA data does show 141 girls registered with the name since 1880.
People living today
38K
~ 1 in 9,110 Americans
Peak year
1952
1,505 babies that year
Average age
54
years old
2024 SSA rank
#794
Tracked since 1880
Census
Rex in the 2020 Census
The 2020 Census recorded 36,165 people with the first name Rex, which placed it at #1,125 in the published first-name tables. This is a snapshot of people who already had the name at the time of the Census.
The SSA sections elsewhere on this page answer a different question: how often parents gave the name to babies over time. The "people living today" figure on this page is different again: it is a current estimate built from SSA birth records and age-based survival rates, so the two numbers are not expected to match exactly.
2020 Census rank
#1,125
National first-name rank
People counted
36K
36,165 in the published race/origin table
Per 100,000
12.0
People with this name in 2020
Largest reported group
White
84.2% of people with this name
Demographics
Ancestry and ethnicity for Rex
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Rex is White at 84.2%. The next largest groups are Asian/Pacific Islander (5.3%) and Black (3.3%). These figures describe the people who had the name in 2020, not any inherent property of the name itself.
The bar chart below shows how people with the first name Rex described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given name, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown so the breakdown is easy to read across every published category. Because the 2020 Census first-name file also includes raw headcounts for each group, Name Census can show those alongside the percentages in the legend and hover tooltip.
Keep in mind that these are self-reported numbers. A first name does not determine a person's race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the name Rex at the time of the 2020 Census, not any inherent property of the name itself.
- White84.2% · 30,445
- Asian and Pacific Islander5.3% · 1,911
- Black or African American3.3% · 1,180
- Two or more races3.2% · 1,164
- Hispanic or Latino3.1% · 1,135
- American Indian and Alaska Native0.9% · 330
Gender
Gender distribution for Rex
Out of the 60,301 babies given the name Rex since 1880, 99.8% were registered as male. The name sits firmly on the male side of the spectrum, with only a handful of female registrations across the entire dataset.
Rex as a male name
- Ranked #794 in 2024
- 316 male births in 2024
- Peak: 1951 (1,503 births)
Rex as a female name
- Ranked #10,051 in 1984
- 6 female births in 1984
- Peak: 1961 (10 births)
2020 Census snapshot
In the 2020 Census sex table, Rex appears almost entirely male. Of the 36,166 people counted with this name, 99.7% were male and only a very small share were female.
Popularity
Rex: popularity over time
The SSA tracks Rex from the 1880s through to the 2020s, spanning 15 decades of birth certificate data. The biggest single decade for the name was the 1950s, with 13,544 total registrations. Usage has dropped considerably from its 1950s peak. The most recent decade brought in only a fraction of the registrations that the name once attracted.
Babies born per year
Decades
Rex by decade
The table below breaks the full SSA timeline into ten-year windows. Each row shows how many male and female babies were given the name Rex during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
Geography
Where Rex' live
The SSA's state-level files cover 48 states and territories. California, Texas, Indiana recorded the most babies named Rex, while Rhode Island, Connecticut, Alaska recorded the fewest. The average across all reporting states is about 1,140 registrations each.
Origin
Meaning and history of Rex
Rex is a masculine given name derived from the Latin word "rex", meaning "king". It originated in ancient Rome during the Roman Republic and Empire periods, and was used as a title for the ruler or sovereign of the Roman state.
The name Rex gained popularity during the Roman era, and was often associated with power, authority, and leadership. It was not uncommon for Roman rulers or members of the nobility to bear this name or use it as a cognomen (a personal surname or nickname).
One of the earliest and most notable historical references to the name Rex can be found in the writings of the Roman historian Livy, who mentioned a Roman general named Quintus Fabius Maximus Rullianus, also known as Rex, who lived in the 4th century BC. Rex was his cognomen, indicating his regal bearing or qualities.
In later centuries, the name Rex continued to be used, albeit less frequently. Some notable individuals with the name Rex throughout history include:
1. Rex Theodericus (454-526 AD), also known as Theodoric the Great, was the king of the Ostrogoths and ruled over a significant portion of the former Western Roman Empire.
2. Rex Horne (1828-1909) was an American politician and lawyer who served as the 13th Governor of North Carolina from 1891 to 1893.
3. Rex Ingram (1892-1950) was an American film director, producer, and screenwriter who directed several notable silent films, including "The Four Horsemen of the Apocalypse" (1921) and "The Prisoner of Zenda" (1922).
4. Rex Stout (1886-1975) was an American crime writer best known for his series of novels featuring the fictional detective Nero Wolfe.
5. Rex Harrison (1908-1990) was an English actor renowned for his performances in films like "Cleopatra" (1963), for which he won an Academy Award, and the stage and film adaptations of "My Fair Lady" (1956 and 1964, respectively).
While the name Rex has retained its association with royalty and leadership over the centuries, it has also taken on additional connotations related to strength, power, and masculinity.
Notable bearers
Famous people named Rex
People
Rex + last name combinations
How many people share a full name with Rex as the first name? Click a combination below to see the estimate, or search any pairing.
Related
Other names starting with R
Other first names starting with R with a similar number of bearers.
FAQ
Rex: questions and answers
How many people in the U.S. are named Rex?
Name Census puts the figure at roughly 37,623 living Americans. We arrive at this by taking every SSA birth registration for Rex going back to 1880 and adjusting each cohort for expected survival using CDC actuarial life tables. The result is an age-weighted living-bearer count, not a raw birth total. That works out to about 1 in 9,110 US residents.
Is Rex a common name?
We classify Rex as "Uncommon". It ranks above 99% of all first names in the SSA dataset by living bearers. Across the full history of the data, 60,301 babies have been registered with this name.
When was Rex most popular?
The single biggest year for Rex was 1952, when 1,505 babies received the name. The fact that the average living Rex is about 54 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
How common was Rex in the 2020 Census?
The published 2020 Census first-name tables recorded 36,165 people with the name Rex, or 11.97 per 100,000 residents. That placed it at #1,125 in the national Census ranking for first names.
Why is the Census count different from the living estimate?
Because they measure different things. The Census figure is a count of people who had the name Rex in 2020. The living estimate aims to answer a current question instead: how many people with the name are alive today, based on SSA birth records and age-based survival rates. Since one number is a 2020 snapshot and the other is a present-day estimate, they are not expected to be identical.
What does the Census say about the gender split for Rex?
In the 2020 Census sex table, Rex appears almost entirely male. Of the 36,166 people counted with this name, 99.7% were male and only a very small share were female. The Census view is a snapshot of people living with the name in 2020, while the SSA section above tracks births across time.
What does the Census say about the background of people named Rex?
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Rex is White at 84.2%. The next largest groups are Asian/Pacific Islander (5.3%) and Black (3.3%). These figures describe the people who had the name in 2020, not any inherent property of the name itself. The percentages in the chart above come from self-reported race and Hispanic-origin responses in the 2020 Census.
Which group reports the name Rex most often in the Census?
White is the largest reported group for people named Rex in the 2020 Census, accounting for 84.2% (30,445 people in the published table).
Why can the Census sex total and race total differ slightly?
The Census Bureau published separate 2020 tables for sex and for race/Hispanic origin, and the released figures can differ slightly because of privacy protection in the public files. That is why this page treats the gender section and the race/origin section as two related snapshots instead of forcing them into one identical total.
Does every first name have Census demographic data?
No. The public Census first-name release only includes names that met the Bureau's publication rules, so many rarer names in the SSA files have no Census demographic snapshot. When that happens, the SSA trend, gender history, and state sections still appear, but the 2020 Census demographic sections are omitted.
What does the SSA popularity chart show?
The chart tracks births, not the number of people alive with the name today. Each point shows how many babies were given the name Rex in that year. That makes it useful for spotting when the name rose, peaked, or faded.
Is Rex a male name?
Yes, 99.8% of people registered as Rex in the SSA data are male. You can see the full per-sex comparison in the gender distribution section above, which includes the latest year rank, birth count, and peak year for each sex.
Is Rex still being used today?
Yes. The SSA still recorded Rex in 2024, and the page above shows its latest-year rank where available. A name can be well past its peak and still remain in steady use, especially if it built up a large population over earlier decades.
Why can a name have a lot of living bearers even if it is not trendy now?
Because living-bearer counts and current baby-name popularity measure different things. A name like Rex can build up a very large population over many decades, even if fewer parents are choosing it now than they did at its peak.
Where does this data come from?
First-name figures come from the Social Security Administration's national baby name files, which cover every name on a birth certificate from 1880 to 2024. Living-bearer estimates layer in CDC actuarial life tables broken out by sex to account for mortality. The population baseline (342,754,338) is the Census Bureau's latest national estimate. You can read the full calculation on our methodology page.
How many people have the name Rex?
For a quick modern take, check how many Americans are named Rex on our sister site HowManyOfMe.org.