How old is someone named Sienna?
The average Sienna is 12 years old.
Half of all living Siennas are between 5 and 18.
When was Sienna popular?
Sienna is a modern favorite: it climbed through the 2000s and hit its high in 2025. 2,659 babies got the name in 2025.
Popular names of 2025 · The most popular names of the 2020s →
Show the numbers by decade
| Born in | Babies born | Alive today |
|---|---|---|
| 1960s | 16 | under 100 |
| 1970s | 102 | under 100 |
| 1980s | 305 | 300 |
| 1990s | 2,151 | 2,100 |
| 2000s | 10,690 | 11,000 |
| 2010s | 14,141 | 14,000 |
| 2020s | 12,482 | 12,000 |
How many Siennas are still alive?
About 40,000 Siennas are alive in the US today. That's over 99% of the roughly 40,000 babies named Sienna since 1960.
Nearly every Sienna ever born is still alive, because almost all of them are young.
What generation is the name Sienna?
More than half of living Siennas are in Gen Alpha, born in 2013 or later.
- Millennial 3%
- Gen Z 40%
- Gen Alpha 56%
Is Sienna an old name?
No. Sienna is one of the youngest names around: younger than 90 in 100 names on AgeByName.
Looking ahead: if babies keep getting the name at today's pace, the typical Sienna will be 25 in 2056, so the name is aging slowly.
Is Sienna a boy or girl name?
Almost entirely girls: over 99.9% of living Siennas are women.
Names the same age as Sienna
NAME TWIN
Sienna's name twin is Cooper. Of all 3,713 names on AgeByName, Cooper's age curve is the closest match to Sienna's: 91% alike.
Other spellings: Siena (13)
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Questions about the name Sienna
How old is the average Sienna?
The average Sienna in the US is 12 years old. The median is 11, so half are older and half younger.
How many people are named Sienna?
About 40,000 Siennas are alive in the US today, out of roughly 40,000 babies given the name since 1960.
When was the name Sienna most popular?
In 2025, when about 2,700 baby girls were named Sienna.
Is Sienna a Gen Alpha name?
Yes. About 56% of living Siennas are in Gen Alpha, born in 2013 or later.
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