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?
  • Molympics
    Estimate! Measure! Analyze! Problem solve! Who will win the gold medal?

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  • 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!)

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(all sites accessed October 2018)

Help Create the Updated
Periodic Table of Moles

What better way to celebrate Mole Day than by creating an element for a periodic table full of moles! Chartered ChemClubs can find more information about how to participate here.

Don't want to create an element, then buy your copy now!