How Many People Are Named Caius?
An estimated 2,058 people in the United States have the first name Caius. It is almost exclusively a male name. The average bearer is 9 years old, and Caius peaked in popularity in 2024 with 205 births that year.
Below you will find a full statistical profile of Caius as a first name in the United States, including gender data, a year-by-year popularity timeline going back to 1880, a decade breakdown, state-by-state birth registrations, and, when available, a 2020 Census snapshot showing who had the name at that point in time. You can also check how many people share the full name Caius paired with any surname.
Key Insights
- Caius is a modern name. With an average bearer age of just 9, it has gained most of its popularity in recent years.
Estimated Living Americans
2,058
About 1 in 166,547 people in the U.S.
Rarity
Rare
Predicted Gender
Male
100.0% confidence
Average Age
9
years old
Peak Year
2024
205 births
Total Registered
2,074
since 1880
Gender Distribution for Caius
Caius is almost exclusively a male name. Out of 2,074 total births registered, 100.0% were male.
Caius as a male name
Ranked #1,061 in 2024
205 male births in 2024
Peak: 2024 (205 births)
Caius in the 2020 Census
The 2020 Census recorded 1,208 people with the first name Caius, which placed it at #10,848 in the published first-name tables. This is a snapshot of people who already had the name in 2020. The estimated living count elsewhere on this page is different: it is a current estimate built from SSA birth records and age-based survival rates, so the two figures are not expected to match exactly.
Read this section as a snapshot of people who already had the name in 2020. The SSA charts elsewhere on this page are still the better way to see how the name rose, fell, or shifted across generations.
Gender in the 2020 Census
In the 2020 Census, Caius was recorded as predominantly male. Out of 1,208 people with this name in that snapshot, 99.6% were male and 0.4% were female. That is very close to the long-run birth pattern in SSA records, where the name is male 100.0% of the time.
Census Count
1,208
people with this name
Census Rank
#10,848
among Census first names
Frequency Rate
0.40
per 100,000 people
Recorded Race and Hispanic Origin in the 2020 Census
In the 2020 Census, the first name Caius was most commonly recorded among people who identified as White (52.15%). The next largest recorded groups were Hispanic (15.07%) and Two or More Races (14.16%).
These percentages describe the people who had the first name Caius in the 2020 Census. They do not tell you the deeper meaning or origin of the name itself.
2020 Census demographic breakdown
Each row shows a recorded Census category for people with the first name Caius.
| Group | Share | Count |
|---|---|---|
| White | 52.15% | 630 |
| Hispanic | 15.07% | 182 |
| Two or More Races | 14.16% | 171 |
| Black | 11.01% | 133 |
| Asian and Pacific Islander | 4.88% | 59 |
| American Indian and Alaska Native | 2.73% | 33 |
Caius: Popularity Over Time
SSA records for Caius span from the 1990s to the 2020s, covering 4 decades of naming data. The most popular decade for this name was the 2010s, when 1,068 babies were registered. While Caius is less common than at its peak in the 2010s, it remains a well-established name with steady registrations.
Caius by Decade
How has Caius tracked across different eras? The table below groups all SSA birth registrations into 10-year periods, with separate male and female counts. The colored bar shows each decade's share relative to the peak.
Caius by State
Birth registrations for Caius span all 28 states and territories in the SSA database. The highest counts are in California, Texas, New York. The lowest are in Oregon, Kentucky, Kansas. On average, about 35 Caiuss were registered per state.
Caius + Last Name Combinations
How many people share a full name with Caius as the first name? Click a combination below to see the estimate, or search any pairing.
Names Similar to Caius
Other first names starting with C with a similar number of bearers.
Caius: Questions and Answers
How many people in the U.S. are named Caius?
We estimate approximately 2,058 people named Caius are alive in the United States today. This is based on SSA birth records from 1880 to 2024, adjusted for mortality using CDC life tables. About 1 in 166,547 Americans share this first name.
Is Caius a common name?
Caius is classified as "Rare" and is more popular than 93.8% of all first names in the SSA database. A total of 2,074 births have been registered with this name since 1880.
When was Caius most popular?
Caius reached peak popularity in 2024, when 205 babies were given this name. The average age of a living person named Caius is approximately 9 years old, reflecting when the name was most commonly given.
How common was Caius in the 2020 Census?
The 2020 Census recorded 1,208 people with the first name Caius. That placed it at #10,848 in the published Census first-name tables, or 0.40 people per 100,000.
Why is the Census count different from the living estimate?
Because they measure different things. The Census number is a count of people with the name in 2020. The living estimate is a current model based on SSA birth records and survival rates, so it aims to estimate how many people with the name are alive now.
What does the SSA popularity chart show?
The popularity chart tracks birth registrations, not people currently alive. It shows how often Caius was given to babies from 1880 through 2024, which is why it is the best tool on the page for seeing long-run naming trends.
What does the Census say about the gender split for Caius?
In the 2020 Census snapshot, Caius was recorded as predominantly male. The published split was 99.6% male and 0.4% female.
What does the Census say about the background of people named Caius?
In the 2020 Census, the first name Caius was most commonly recorded among people who identified as White (52.15%). The next largest recorded groups were Hispanic (15.07%) and Two or More Races (14.16%). These percentages describe the people who had the name in the 2020 Census, not the deeper meaning or origin of the name itself.
Why can the Census sex total and race total differ slightly?
The Census published separate first-name tables for sex and for race and Hispanic origin. Those totals can differ slightly for the same name, so the page uses them as two related snapshots rather than treating them as perfectly interchangeable counts.
Does every first name have Census demographic data?
No. The public Census first-name tables only include names that met the Bureau's publication rules. That means some names on this site will have SSA history but no published Census demographic snapshot.
Is Caius a male name?
Caius is predominantly male. 100.0% of people with this name are male. See the gender breakdown above for full details.
Why can Caius have a lot of living bearers even if it is not trendy now?
Because a name can build up a large population over many decades. Caius peaked in 2024, and the average living bearer is about 9 years old, so a name can still have millions of living bearers even after it stops feeling current for newborns.
How many Caius Smiths are there?
To find how many people share a specific full name, we combine first name and surname frequencies. Try: Caius Smith, Caius Johnson, Caius Williams. You can also search any combination on our homepage.
Where does this data come from?
Our estimates use Social Security Administration birth records (1880 to 2024), adjusted for survival using CDC 2023 life tables broken down by sex. The U.S. population figure (342,754,338) is from the Census Bureau's July 2025 estimate. Full methodology.
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