What year was I born if I'm 21?
2004 or 2005
Anyone who is 21 today, Thursday, September 24, 2026, was born between Saturday, September 25, 2004 and Saturday, September 24, 2005. The boundary falls in the middle of the year, so the answer spans two of them.
- Earliest birth date
- September 25, 2004
- Latest birth date
- September 24, 2005
- Birth years
- 2004 or 2005
- Age today
- 21
Which year, exactly
Someone born on Saturday, September 24, 2005 turns 21 today. Someone born a day later, on Sunday, September 25, 2005, is still 20 until tomorrow. That is why “what year” has two answers rather than one, and why a birth date rather than a year is what settles it.
Read the other way round: to be exactly 21 today, a date of birth has to fall on or after Saturday, September 25, 2004 and on or before Saturday, September 24, 2005.
There is no 29 February in that window, so everyone who is 21 today has had a birthday every year since they were born. Twenty-five of the hundred ages on this site do span a leap day; this is not one of them.
The two candidate years
- Born in 2004from September 25, 2004
- Born in 2005up to September 24, 2005