Theo vs Theodorus
American parents have registered 39,333 Theos since 1880, against 35 Theodoruses. Theo is still ahead, with 3,966 babies in 2025.
Babies given each name, 1880–2025
Theo Theodorus
Each line is every baby given the name that year, girls and boys added together — the only count that means the same thing for both names. A line breaks where the name fell below five babies in a year — the point at which the SSA stops publishing it — rather than being drawn through a figure nobody published. A single published year in a gap shows as a dot.
Who was ahead
Theo has been the commoner name in every year either was published, 1880 to 2025. The lead has never changed hands.
The closest they came was 2024, when Theo had 4,160 and Theodorus had 14.
Side by side
| Theo | Theodorus | |
|---|---|---|
| Total US births | 39,333 | 35 |
| Most in one year | 4,182 | 14 |
| Babies in 2025 | 3,966 | 5 |
| Estimated living today | 33,000 | 40 |
| Median age today | 4 | 1 |
| Peak year | 2023 | 2024 |
| Best rank | 78th boys | 6,199th boys |
| Rank in 2025 | 82nd | 12,008th |
| First recorded | 1880 | 2020 |
| Girls / boys | 3,503 / 35,830 | 0 / 35 |
A rank is a position within one sex’s list for one year, so the two rank rows are not subtracted from one another and the winning column is not marked on them. The living figure is a life-table estimate, not a count.
Which name is older
Half of the Theos alive today are over 4; half the Theodoruses are over 1. That is 3 years between them: two names in use at the same time, worn by two different generations.
Both names abroad
Countries whose statistics office publishes both names, so the comparison can be made somewhere other than the United States.
| Country | Theo | Theodorus |
|---|---|---|
| France | 133,745 Théo | 5 |
| England and Wales | 43,001 | 6 |
Every spelling a country files separately is added together, over whatever years that country publishes — which is not the same range in any two of them, so read the columns against each other and not the rows.
Compare something else
Related comparisons
Social Security Administration birth records, 1880–2025, public domain. Full histories: Theo and Theodorus.