Kelvin

This name is sometimes used—and sometimes mistaken—as a variant of Calvin.
https://www.behindthename.com/name/calvin

---

Also of Brazilian Portuguese usage.
https://www.behindthename.com/name/kelvin/top/brazil

---

Also really popular in English-speaking African countries—especially East Africa (Kenya and Tanzania).
https://forebears.io/forenames/kelvin

Also Dutch: https://nvb.meertens.knaw.nl/naam/is/Kelvin

Also Portuguese (Brazilian): https://www.behindthename.com/name/kelvin/top/brazil

The name Kelvin was given to 335 boys born in the US in 2016.
More than 99.9 percent of people with the first name Kelvin are male.

A proud Kelvin since birth in 1942, I have only met one other Kelvin. I was standing in line in Boston to pick up theater tickets where we had to give our name. I overheard the gentleman in front of me give his name as "Kelvin Xyz". I clapped him on the shoulder and enthused about my first ever Kelvin encounter. He said that he had been born in New Zealand and down there Kelvin was as common as Keith or Kenneth, if not more so. I don't know if this is born out by the stats. Still, an interesting data point.