Mole Day

Student with a mole cake
Auburndale High School, Auburndale, FL

Celebrated annually on October 23 from 6:02 a.m. to 6:02 p.m., Mole Daycommemorates Avogadro's Number (6.02 x 1023), which is a basic measuring unit in chemistry. Find ways to celebrate this chemistry “holiday” with the links below.

Mole Day also typically falls during National Chemistry Week—an annual event that unites American Chemical Society Local Sections, businesses, schools, and individuals in communicating the importance of chemistry in everyday life.

National Mole Day Foundation is your go-to source for all things Mole Day. Jokes, history, themes, store—they’ve got it all. Don’t miss the “Fabulous Mole Projects” gallery.


  • How Big Is a Mole?
    Step 1: Consider a mole of cans of Spam. Step 2: Compare its weight to the weight of all the gold in the U.S. Treasury. Step 3: Make a poster about it.
  • Getting Ready for Mole Day
    Whip up a batch of Grandma Button’s Molasses Cookies to celebrate Mole Day. But first, can you translate the recipe?

Youtube ID: U1frmqkNqW0

  • Chemical Quantities Activities
    Just in case you wanted to dedicate part of Mole Day to, you know, learning something… Take a look at this collection of worksheets, puzzles, and labs about moles.
  • Molar Whack
    Chemistry meets the arcade in this online game. Whack a mole on the head—how many points can you earn? (Tip: Hit elements with the highest molar mass!)

Youtube ID: oIkC7SRqXP0

  • Chemists' Holiday
    6.022 x 1023. Just how large a number is that? These statistics can help make it clearer.
  • Mole Day Celebration
    Scratching your head trying to come up with ideas on how to celebrate Mole Day? Look no further!

Youtube ID: TEl4jeETVmg

  • Mole Day Jokes
    What did Avogadro teach his students in math class? What’s his favorite kind of music? Share these mole jokes!
  • Mole Photo
    A student asks, “I just found this really weird mole on my hand. Should I get it checked?” Take a look at the photo and see what you think.

Youtube ID: ReMe348Im2w

Get the new
Periodic Table of Moles

What better way to celebrate Mole Day than with a periodic table full of moles! Buy your copy now!