How old is someone named Guillermo?
The average Guillermo is 33 years old.
Half of all living Guillermos are between 19 and 45.
When was Guillermo popular?
Few names are as steady as Guillermo. It peaked in 1998, but babies have been named Guillermo every year since records began, and 264 were in 2025.
Popular names of 1998 · The most popular names of the 1990s →
Show the numbers by decade
| Born in | Babies born | Alive today |
|---|---|---|
| 1900s | 44 | 0 |
| 1910s | 253 | 0 |
| 1920s | 821 | under 100 |
| 1930s | 783 | under 100 |
| 1940s | 943 | 420 |
| 1950s | 1,495 | 990 |
| 1960s | 2,112 | 1,700 |
| 1970s | 3,362 | 3,000 |
| 1980s | 4,388 | 4,100 |
| 1990s | 6,496 | 6,300 |
| 2000s | 6,100 | 6,000 |
| 2010s | 3,615 | 3,600 |
| 2020s | 1,718 | 1,700 |
How many Guillermos are still alive?
About 28,000 Guillermos are alive in the US today. That's 87% of the roughly 32,000 babies named Guillermo since 1885.
Most Guillermos ever born are still alive.
What generation is the name Guillermo?
About one in three living Guillermos are in Gen Z, born between 1997 and 2012.
Is Guillermo an old name?
Somewhat. Guillermo is older than 56 in 100 names on AgeByName, but younger than plenty of classics.
Looking ahead: if babies keep getting the name at today's pace, the typical Guillermo will be 46 in 2056, so the name is aging slowly.
Is Guillermo a boy or girl name?
Almost entirely boys: 99.7% of living Guillermos are men.
Names the same age as Guillermo
NAME TWIN
Guillermo's name twin is Francisco. Of all 3,713 names on AgeByName, Francisco's age curve is the closest match to Guillermo's: 97% alike.
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Questions about the name Guillermo
How old is the average Guillermo?
The average Guillermo in the US is 33 years old. The median is 31, so half are older and half younger.
How many people are named Guillermo?
About 28,000 Guillermos are alive in the US today, out of roughly 32,000 babies given the name since 1885.
When was the name Guillermo most popular?
In 1998, when about 690 baby boys were named Guillermo.
Is Guillermo a Gen Z name?
Partly. Gen Z are the largest group, about 33% of living Guillermos, but the name spans several generations.
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