How Many People Are Named Duncan?
An estimated 17,392 people in the United States have the first name Duncan. It is almost exclusively a male name. The average bearer is 34 years old, and Duncan peaked in popularity in 1997 with 644 births that year.
Below you will find a full statistical profile of Duncan 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 Duncan paired with any surname.
Estimated Living Americans
17,392
About 1 in 19,708 people in the U.S.
Rarity
Uncommon
Predicted Gender
Male
99.9% confidence
Average Age
34
years old
Peak Year
1997
644 births
Total Registered
21,043
since 1880
Gender Distribution for Duncan
Duncan is almost exclusively a male name. Out of 21,043 total births registered, 99.9% were male.
Duncan as a male name
Ranked #1,102 in 2024
194 male births in 2024
Peak: 1997 (644 births)
Duncan as a female name
Ranked #17,190 in 2015
5 female births in 2015
Peak: 1996 (6 births)
Duncan in the 2020 Census
The 2020 Census recorded 17,445 people with the first name Duncan, which placed it at #1,737 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, Duncan was recorded as predominantly male. Out of 17,445 people with this name in that snapshot, 99.4% were male and 0.6% were female. That is very close to the long-run birth pattern in SSA records, where the name is male 99.9% of the time.
Census Count
17,445
people with this name
Census Rank
#1,737
among Census first names
Frequency Rate
5.78
per 100,000 people
Recorded Race and Hispanic Origin in the 2020 Census
In the 2020 Census, the first name Duncan was most commonly recorded among people who identified as White (83.33%). The next largest recorded groups were Black (5.60%) and Two or More Races (5.15%).
These percentages describe the people who had the first name Duncan 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 Duncan.
| Group | Share | Count |
|---|---|---|
| White | 83.33% | 14,536 |
| Black | 5.60% | 976 |
| Two or More Races | 5.15% | 899 |
| Hispanic | 3.63% | 634 |
| Asian and Pacific Islander | 1.85% | 322 |
| American Indian and Alaska Native | 0.44% | 77 |
The Census published separate sex and race/origin tables for first names, so their total counts can differ slightly for the same name. That is why the race section focuses on the demographic mix rather than repeating a second headline count.
Duncan: Popularity Over Time
SSA records for Duncan span from the 1880s to the 2020s, covering 15 decades of naming data. The most popular decade for this name was the 1990s, when 4,227 babies were registered. Duncan has declined significantly from its peak in the 1990s. Recent registrations are a fraction of what they were at the name's height.
Duncan by Decade
How has Duncan 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.
Duncan by State
Birth registrations for Duncan span all 47 states and territories in the SSA database. The highest counts are in California, New York, Texas. The lowest are in Wyoming, North Dakota, Hawaii. On average, about 320 Duncans were registered per state.
Duncan + Last Name Combinations
How many people share a full name with Duncan as the first name? Click a combination below to see the estimate, or search any pairing.
Names Similar to Duncan
Other first names starting with D with a similar number of bearers.
Duncan: Questions and Answers
How many people in the U.S. are named Duncan?
We estimate approximately 17,392 people named Duncan 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 19,708 Americans share this first name.
Is Duncan a common name?
Duncan is classified as "Uncommon" and is more popular than 98.4% of all first names in the SSA database. A total of 21,043 births have been registered with this name since 1880.
When was Duncan most popular?
Duncan reached peak popularity in 1997, when 644 babies were given this name. The average age of a living person named Duncan is approximately 34 years old, reflecting when the name was most commonly given.
How common was Duncan in the 2020 Census?
The 2020 Census recorded 17,445 people with the first name Duncan. That placed it at #1,737 in the published Census first-name tables, or 5.78 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 Duncan 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 Duncan?
In the 2020 Census snapshot, Duncan was recorded as predominantly male. The published split was 99.4% male and 0.6% female.
What does the Census say about the background of people named Duncan?
In the 2020 Census, the first name Duncan was most commonly recorded among people who identified as White (83.33%). The next largest recorded groups were Black (5.60%) and Two or More Races (5.15%). 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 Duncan a male name?
Duncan is predominantly male. 99.9% of people with this name are male. See the gender breakdown above for full details.
Why can Duncan 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. Duncan peaked in 1997, and the average living bearer is about 34 years old, so a name can still have millions of living bearers even after it stops feeling current for newborns.
How many Duncan Smiths are there?
To find how many people share a specific full name, we combine first name and surname frequencies. Try: Duncan Smith, Duncan Johnson, Duncan 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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