How old is someone named Gillian?
The average Gillian is 31 years old.
Half of all living Gillians are between 23 and 39.
When was Gillian popular?
Gillian had one big moment, peaking in 1999. 54% of the babies ever named Gillian arrived in a single 15-year stretch.
Popular names of 1999 · The most popular names of the 1990s →
Show the numbers by decade
| Born in | Babies born | Alive today |
|---|---|---|
| 1920s | 5 | 0 |
| 1930s | 12 | 0 |
| 1940s | 128 | under 100 |
| 1950s | 234 | 190 |
| 1960s | 758 | 670 |
| 1970s | 1,337 | 1,300 |
| 1980s | 2,399 | 2,300 |
| 1990s | 4,172 | 4,100 |
| 2000s | 5,503 | 5,400 |
| 2010s | 1,274 | 1,300 |
| 2020s | 305 | 310 |
How many Gillians are still alive?
About 16,000 Gillians are alive in the US today. That's 97% of the roughly 16,000 babies named Gillian since 1922.
Nearly every Gillian ever born is still alive, because almost all of them are young.
What generation is the name Gillian?
About half of living Gillians are in Gen Z, born between 1997 and 2012.
- Boomer 3%
- Gen X 12%
- Millennial 24%
- Gen Z 55%
- Gen Alpha 6%
Is Gillian an old name?
Somewhat. Gillian is older than 53 in 100 names on AgeByName, but younger than plenty of classics.
Is Gillian a boy or girl name?
Almost entirely girls: 99.6% of living Gillians are women.
Names the same age as Gillian
NAME TWIN
Gillian's name twin is Brendan. Of all 3,713 names on AgeByName, Brendan's age curve is the closest match to Gillian's: 87% alike.
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Questions about the name Gillian
How old is the average Gillian?
The average Gillian in the US is 31 years old. The median is 27, so half are older and half younger.
How many people are named Gillian?
About 16,000 Gillians are alive in the US today, out of roughly 16,000 babies given the name since 1922.
When was the name Gillian most popular?
In 1999, when about 1,000 baby girls were named Gillian.
Is Gillian a Gen Z name?
Yes. About 55% of living Gillians are in Gen Z, born between 1997 and 2012.
Estimates from Social Security Administration baby-name records (births 1880–2025) and SSA cohort life tables (2026 Trustees Report). Updated each spring. How we calculate this