Caio vs Rei

Baby Name Comparison — 2026

Caio

Boy #3,730 Most Popular 3 Syllables

Meaning

"to rejoice, to be glad"

Origin: Latin

Cultural Roots

Brazilian Portuguese Italian Roman

Quick Stats

Popularity Rank
#3,730
Total SSA Count
30
Syllables
3
Formality
Moderate
Nicknames
Kai, Ca

Playground Safety Score

✓ All Clear
Full profile for Caio →

Rei

Boy #3,800 Most Popular 1 Syllable

Meaning

"courtesy, respect, gratitude"

Origin: Japanese kanji 礼

Cultural Roots

Japanese American Brazilian

Quick Stats

Popularity Rank
#3,800
Total SSA Count
29
Syllables
1
Formality
Moderate

Playground Safety Score

✓ All Clear
Full profile for Rei →

Popularity Comparison

Caio Rank #3,730
Rei Rank #3,800

Caio is more popular, ranked #3730 vs #3800 for Rei.

Popularity Over Time

Historical US popularity rank — lower number means more popular.

Middle Name Pairings

Caio ___

  • Caio Alexandre
  • Caio Felipe
  • Caio Henrique
  • Caio Lucas
  • Caio Rafael
  • Caio Miguel

Rei ___

  • Rei James
  • Rei Thomas
  • Rei Alexander
  • Rei Kenji
  • Rei Haruki
  • Rei Jun

Sibling Name Ideas

Names that pair well as siblings.

If you choose Caio

Enzo Mateus Pedro Giovanna Isadora

If you choose Rei

Kai Sora Haru Ryu Suki

Which Name Fits Your Family?

Answer 3 quick questions and we'll help you decide.

1. Which style feels more like your family?

Frequently Asked Questions

Is Caio or Rei more popular?

Caio is more popular, ranked #3730 compared to Rei at #3800 in the United States.

What do Caio and Rei mean?

Caio means "to rejoice, to be glad" (Latin origin). Rei means "courtesy, respect, gratitude" (Japanese kanji 礼 origin).

Are Caio and Rei boy or girl names?

Caio is primarily a boy name. Rei is primarily a boy name.

More Comparisons

Rei vs Caio Caio vs Owais Caio vs Tytan Caio vs Breeze Caio vs Yadriel
← Full profile: Caio ← Full profile: Rei Browse all baby names