The actual number of jelly beans in a quart size mason jar is 321 – we counted! You need to know the number of jellybeans if you’re trying to win the Guess How Many In The Jar jelly bean game, right? We got you!

guess how many in the jar sign with a mason jar of jelly beans, pens and cards for making guesses
Can you gues how man jelly beans are in a Mason jar?

Factors Affecting the Number of Jelly Beans That Fit in a Mason Jar

The cereal being counted

The brand or type of jelly beans can make a difference because the size can vary between different manufacturers. To be precise, we used Brach’s jelly beans. Jelly belly beans are another popular choice of jelly beans, but they are smaller so make sure you know which kind are being used.

It also matters how close the jelly beans get to the top of the jar. We completely filled our jar to the rim.

What are jelly beans?

Jelly beans have a surprisingly long and interesting history! The treat as we know it today first made its appearance in 1861, when Boston confectioner William Schrafft urged people to send his jellybeans to soldiers during the American Civil War. They were advertised as being a delicious, nutritious snack that was easy to transport.

The original jelly beans were a mix of fruit flavors, such as lemon, lime, orange, and raspberry. Over the years, more unique flavor options became popular. Ronald Reagan famously requested “jelly bellies” to be served at his presidential inauguration – setting off a jelly bean craze that continues today!

Jelly beans are made from a variety of different ingredients, depending on the flavor. Some common ingredients include sugar, corn syrup, and artificial flavors and colors.

The jar used for the Guess How Many game

Not everyone uses a quart sized mason jar for this game. Some use other sizes, and others use entirely different kinds of jars or transparent containers.

We used a classic wide mouth glass 64 oz quart mason jar.

Guess How Many In The Jar Formula and Conversion Facts

There will always be some variation of the amount of beans depending on how high the jar is filled, but this ought to get you pretty close to the correct number and winning the prize!

Volume of the Jar Formula

The best formula for estimating the volume of a round jar is how to calculate the volume of a cylinder using the formula V = π r2 h.

This means the volume is equal to pi multiplied by the radius squared multiplied by the height of the jar.


  • pi = 3.14
  • the radius of the jar is half of the width.
  • the square of the radius is the same as multiplying the radius times itself.
  • fill the numbers into the formula and multiply to get a good approximate volume of the jelly beans.
  • finally, divide by the volume of a single jelly bean (about 3.5 cubic centimeters) to arrive at a close estimate of the correct number of jelly beans

Jar Calculator Conversions

You need to know the size of the jar too. We use a 64 oz mason jar (A 64 oz jar is the same as a quart jar.)

If it’s not a quart sized jar then you’ll have to do some calculating:

  • A pint-sized mason jar is 1/2 of a quart, so 321 / 2= 160
  • There are two quarts in a half gallon, so 321 x 2 = 642
  • There are four quarts in a gallon, so 321 x 4 = 1,284

Are they describing the jar in terms of ounces? Here are some conversions for you:

  • A pint size jar is also a 16 ounce jar
  • A quart size jar is also a 32 ounce jar
  • A half gallon size jar is a 64 ounce jar
  • A gallon size jar is a 128 ounce jar

These size references for jars are fluid ounces!

More about ounces

  • ‘oz.’ is the abbreviation for ‘ounce’!
top view of jelly beans in a quart mason jar for the guess how many in the jar game
That’s a lot of jelly beans!

Let’s Play Guess How Many In The Mason Jar!

Want to play Guess How Many In The Jar at your next party?

Grab a quart sized mason jar, a 64 oz bag or larger of pumpkin seeds or your favorite candy then head on over to Skip to my Lou for step by step instructions plus the awesome free printable signs and cards for the Guess How Many In The Jar Game you see in these photos!

More How Many Fit In a Mason Jar Counts:

Tell us – what did you guess and how close were you?

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