How old is someone named Millie?
The average Millie is 19 years old.
Half of all living Millies are between 3 and 18. The average sits between a large young group and an older one, so many Millies are much younger than 19.
When was Millie popular?
Millie is a comeback name. It was common in the early 1900s, nearly disappeared by mid-century, and has returned, peaking again in 2025.
Popular names of 2025 · The most popular names of the 2020s →
Show the numbers by decade
| Born in | Babies born | Alive today |
|---|---|---|
| 1900s | 1,995 | 0 |
| 1910s | 4,190 | 0 |
| 1920s | 3,978 | under 100 |
| 1930s | 2,633 | 540 |
| 1940s | 2,282 | 1,300 |
| 1950s | 1,932 | 1,500 |
| 1960s | 1,289 | 1,100 |
| 1970s | 741 | 690 |
| 1980s | 462 | 450 |
| 1990s | 472 | 460 |
| 2000s | 1,578 | 1,600 |
| 2010s | 6,860 | 6,800 |
| 2020s | 14,240 | 14,000 |
How many Millies are still alive?
About 29,000 Millies are alive in the US today. That's 62% of the roughly 46,000 babies named Millie since 1880.
Roughly half of all Millies ever born are still living.
What generation is the name Millie?
About two in three living Millies are in Gen Alpha, born in 2013 or later.
Is Millie an old name?
Not really. Millie is younger than 72 in 100 names on AgeByName.
Looking ahead: if babies keep getting the name at today's pace, the typical Millie will be 21 in 2056, about the same as today.
Is Millie a boy or girl name?
Almost entirely girls: over 99.9% of living Millies are women.
Names the same age as Millie
NAME TWIN
Millie's name twin is Margot. Of all 3,713 names on AgeByName, Margot's age curve is the closest match to Millie's: 91% alike.
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Questions about the name Millie
How old is the average Millie?
The average Millie in the US is 19 years old. The median is 7, so half are older and half younger.
How many people are named Millie?
About 29,000 Millies are alive in the US today, out of roughly 46,000 babies given the name since 1880.
When was the name Millie most popular?
In 2025, when about 3,400 baby girls were named Millie.
Is Millie a Gen Alpha name?
Yes. About 70% of living Millies 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