Bar Mitzvah gifts

I’m attending a Bar Mtzvah for the first time and was doing a bit of research on appropriate and/or traditional gifts.

One bit of information I came across was the tradition of giving cash as a gift, but in increments of $18.00 ($18, 36, 54…)

This sounds like my best option, as I’m not really sure what the boy’s into, but I’m curious about the “18”.

Anyone know where this comes from and what is the significance?

Thanks!

If you map the letters of Hebrew to their numeric equivalents (analogous to A=1, B=2, C=3, etc.), the word C’hai, which means “life”, has a value of 18. For this reason, giving thing in multiples of 18 is considered a way of wishing the recipient life (or long life, or good life)

-Muttrox, who is such a lapsed jew he is not at temple on this most holy day but instead at work and surfing SMDB

Thanks! I never would have guessed that.