Chai
KHAI (rhymes with “high”) · חי · Hebrew
What does chai mean?
Chai is the Hebrew word for “life” or “living,” spelled with two letters, chet and yud. It shows up everywhere in Jewish life, from jewelry to toasts, as a compact way of saying: here’s to being alive, and staying that way.
Two letters, one idea
Chet and yud aren’t just chai’s spelling, they’re also numbers. In gematria, the Hebrew system that assigns a value to every letter, chet equals 8 and yud equals 10. Together they add up to 18, which is why 18 became the number associated with life itself.
Gematria value
Chet (8) + yud (10) = 18.
Why gifts come in multiples of 18
Because chai equals 18, giving money in multiples of that number became a way of wishing someone a long, good life along with the gift itself. $18 is the classic amount at a bar or bat mitzvah, wedding, or new baby. $36, “double chai,” steps it up a level, and $54 or $180 keep the same idea going. It’s less about the math and more about tucking a blessing into an envelope. Practices vary by family and community, and plenty of people give in round numbers instead, but the 18 tradition is common enough that it’s worth knowing before your next simcha.
We put this word on a shirt. See the collection.