The Haunted Library · updated October 25, 2026

The best Halloween candy math on the internet

31 candy experiments, games and true stories from around the internet. Each has a real number and a question to try.

Every link checked by hand, October 25, 2026.

Start here

Count & estimateHow many Skittles packs until two match exactly?468 packs openedPrices & marketsA real candy trading floor, reported by NPR25 kids, one living roomGames & puzzlesChomp: the chocolate bar with one poisoned square1st player can always winMyth vs. mathThe poisoned-candy myth, checked for 60 years0 confirmed cases of strangers harming trick-or-treaters this way

Count & estimate

Jars, packs and licks: real people counting real candy.

468 packs opened

How many Skittles packs until two match exactly?

A blogger predicted it would take 400 to 500 packs. Pack 464 matched.

Possibly Wrong · Experiment

Try this

This is the birthday problem in a candy wrapper. How many people do you need in a room before two probably share a birthday? Guess first, then look it up (it’s 23).

A math blogger predicted it would take roughly 400 to 500 packs to find two with the exact same colors, then spent 82 days counting 27,740 Skittles to check. The match showed up right on schedule.

By the Possibly Wrong blog. Open it

Also: FlowingData’s write-upA 2020 math paper on the same question

Pairs with Log your haul

68–71% of a jar is candy

Why M&M’s pack tighter than marbles

Squashed spheres fill more of a jar than balls do. Physicists proved it with candy.

Physics World · Science study

Try this

Guessing the candy jar? Find the jar’s volume, multiply by 0.7, and divide by the volume of one M&M. Then compare with your plain guess.

Physicists poured M&M’s into containers and found they fill 68 to 71% of the space at random. Round balls only fill about 64%. Being a little squashed lets each M&M touch more neighbors. They published it in Science in 2004.

By Paul Chaikin and colleagues (Princeton & Cornell). Open it

Also: The paper in Science (2004)

Pairs with Log your haul

712 M&M’s sorted by color

The M&M color mystery that a factory solved

A statistician’s colors didn’t match the official mix. Then Mars admitted it has two factories.

R-bloggers · Statistics

Try this

Sort a few fun-size bags by color. Does your mix look like one factory, the other, or neither? How many bags would you need to be sure?

A statistician scooped M&M’s from the office break room for weeks. His colors didn’t match the mix Mars had published, and a chi-square test said that probably wasn’t luck. Then Mars explained: two factories make M&M’s, each with its own color mix.

By Rick Wicklin (SAS), re-run in R by Chuck Powell. Open it

Pairs with Log your haulCandy Report

144 to 411 licks, depending on who asked

How many licks to the center of a Tootsie Pop?

A machine said 364. Kids said 252. Another machine said 411. Who’s right?

Tootsie · Experiments

Try this

Why don’t they agree? Write your own rule for what counts as one lick, then test it on 3 pops. Is your answer a single number or a range?

Purdue engineers built a licking machine: 364 licks. Their 20 human volunteers: 252. A University of Michigan machine: 411. Junior high students at Swarthmore: 144. Same candy, four answers.

By Tootsie Roll Industries. Open it

Pairs with Log your haul

within 1% the crowd’s middle guess

The crowd that guessed an ox’s weight

800 people guessed. Most were wrong. Their middle guess was off by 9 pounds.

Wikipedia · Classic study

Try this

At a party, have everyone guess the candy jar without talking. Line the guesses up and take the middle one. Did the crowd beat the best single guesser?

In 1906, about 800 people at an English fair guessed the weight of an ox. Most were off, but the middle guess (1,207 pounds) was within 1% of the real weight (1,198). It’s the reason candy-jar contests are secretly a math lesson.

By Wikipedia editors. Open it

Pairs with Log your haul

1,203 pumpkins measured and weighed

Weighing a giant pumpkin with a tape measure

Growers turned 1,203 pumpkins into a chart that weighs with a tape measure.

BigPumpkins.com · Data tables

Try this

Measure around your own pumpkin, then weigh it. Do it with 5 pumpkins and plot circumference against weight. Is it a straight line? (Hint: think about volume.)

Giant pumpkin growers can’t put a 1,500-pound pumpkin on a bathroom scale, so they built tables from 1,203 real pumpkins to turn tape-measure readings into a weight. They also tell you how often the estimate misses: about 76% land within 10%.

By Len Stellpflug and David Martin. Open it

132.7M occupied homes in the U.S.

132.7 million doors to knock on

Every Halloween, the Census counts the doors. And the kids. And the spooky towns.

Census · Facts for Features · Government data · free data

Try this

72.0 million kids and 132.7 million homes: about how many kids per home? Why might your street feel very different from that average?

Every year the Census Bureau posts Halloween facts: how many homes there are (potential stops), how many kids (72.0 million), and towns with spooky names like Sleepy Hollow, Illinois.

By U.S. Census Bureau. Open it

Pairs with Log your haul

Prices & markets

What candy costs, who sets the price, and why factories move.

25 kids, one living room

A real candy trading floor, reported by NPR

One kid cornered the Reese’s market by trading first. Charleston Chews never moved.

NPR · The Salt · Reporting

Try this

Spot the market ideas: who used supply, who used timing, which candy acted like pennies? Then try one rule at your own trading floor.

A reporter watched 25 kids, most about 11, trade after trick-or-treating. One cornered the Reese’s market by trading early. One worked hard to unload extra candy from her own house. Charleston Chews barely moved at all.

By Kristofor Husted. Open it

Pairs with After the haul

33 → 4.5 minutes of work per bar

A Hershey bar cost 33 minutes of work in 1900

The price stayed 5 cents for 69 years. What changed was how long you worked for it.

Human Progress · Analysis

Try this

Find your own time price: how many minutes of chores or allowance pays for one full-size bar? Is candy cheap or expensive for you?

A Hershey bar cost 5 cents from 1900 until 1969. That sounds cheap until you divide by wages: an unskilled worker earned about 9 cents an hour in 1900. By 2022 the bar cost $1.15, but only about 4.5 minutes of work.

By Gale L. Pooley. Open it

Also: Candy prices over the years

Pairs with After the haul

$4.8M vs $10.2M sugar savings vs. wage savings

Why Life Savers left America (depending on who you ask)

Two sides, two sets of real numbers, one factory move. Decide who’s right.

NPR · Potato Grower · Two sides

Try this

Both sides used real numbers. What would you need to know to decide who’s right? Who gains from each story?

In 2002 the maker of Life Savers announced it was moving production from Michigan to Canada and blamed high U.S. sugar prices. The sugar growers’ group did its own math: at most $4.8 million a year saved on sugar, but about $10.2 million on wages.

By Jackie Northam (NPR) and the American Sugar Alliance. Open it

Also: The sugar growers’ math

Pairs with Candy trends

$12,000 a ton of cocoa at the 2024 peak

Cocoa got 4× pricier. Read the label.

When cocoa hit $12,000 a ton, some candy quietly changed what was inside.

The Guardian · Reporting + data

Try this

Pull the monthly cocoa price yourself from FRED (series PCOCOUSDM). By what percent did it rise from its 2022 average to its peak?

Bad weather and disease in West Africa sent cocoa from about $2,000–3,000 a ton to $12,000. Some candy makers quietly swapped cocoa for cheaper ingredients. This is the story behind our Candy trends chart.

By The Guardian; price data from FRED. Open it

Also: Cocoa price data (FRED)

Pairs with Candy trends

$1 per pound

Dentists who buy candy for $1 a pound

About 300 dentists did it in 2007. More than 2,500 did by 2014.

NPR · The Salt · Reporting

Try this

Weigh your extra candy. What would a buyback pay you? Now compare with what that candy cost in the store. Who gets the better deal, and why might you still say yes?

A Wisconsin dentist started paying kids $1 a pound for extra candy and shipping it to troops overseas. About 300 dentists joined in 2007. By 2014 it was more than 2,500.

By Allison Aubrey. Open it

Also: Operation Gratitude

Pairs with After the haul

2007 the year daylight saving moved past Halloween

Did candy makers win an extra hour of Halloween daylight?

A 2005 law kept Halloween evening lighter. Candy makers were called “winners.”

NBC News · Reporting

Try this

Look up sunset time in your town on October 31. What would it be one hour earlier? How many minutes of daylight trick-or-treating does that change?

A 2005 law pushed the end of daylight saving time into November, so Halloween stayed lighter in the evening. NBC listed candy as a “winner.” The candy industry is widely thought to have lobbied for it; its trade group says that’s not so.

By NBC News. Open it

$13.5B planned Halloween spending, 2026

Where America’s $13.5 billion Halloween goes

Every year, thousands of shoppers say what they’ll spend. Candy always tops the list.

NRF · Data hub

Try this

Divide this year’s candy spending by the number of U.S. kids (72 million, from the Census). Is that the cost of one kid’s haul? What’s missing from that math?

Every year the NRF surveys thousands of shoppers about costumes, candy and decorations. Candy is the item the most people buy. The yearly numbers make a great line chart.

By National Retail Federation. Open it

Pairs with Candy trends

630M lb Illinois pumpkins, 2022

One state grows more pumpkins than the next five combined

Illinois grew 630 million pounds in 2022. Most of it went into cans.

USDA ERS · Government chart · free data

Try this

What fraction of the top six’s pumpkins came from Illinois? Draw it as a pie with six slices (Indiana 160, California 120, Michigan 90, Pennsylvania 90, Virginia 50).

The top six pumpkin states grew about 1.2 billion pounds in 2022, and Illinois grew 630 million of them. Most Illinois pumpkins go into cans, not onto porches.

By Gregory Astill, USDA Economic Research Service. Open it

Also: Why Illinois wins

Polls & rankings

Who decides the best candy, and how they measured it.

269,000 matchups

The candy power ranking: 269,000 head-to-head votes

Two candies at a time, 269,000 times. Reese’s won 84% of its matchups.

FiveThirtyEight (archived) · Poll + open data · free data

Try this

Download the spreadsheet. Do chocolate candies win more often than fruity ones? Make two lists and average each.

Instead of asking “what’s your favorite?”, FiveThirtyEight showed people two candies at a time. Reese’s Peanut Butter Cups won 84% of its matchups. The data that seeds our Sweet 16 comes from here, and it’s free to download.

By Walt Hickey, FiveThirtyEight. Open it

Also: The data on GitHub

Pairs with Candy Sweet 16

2,460 people surveyed in 2017

The Candy Hierarchy: joy minus despair

Votes for JOY minus votes for DESPAIR. The raw survey is free to download.

The Science Creative Quarterly (UBC) · Survey + open data · free data

Try this

Make your own Net Feelies at home: ask 10 people JOY, MEH or DESPAIR for 5 candies. Which candy is the most divisive (lots of both)?

Two scientists have ranked Halloween candy for years with a tongue-in-cheek score called Net Feelies: votes for JOY minus votes for DESPAIR. The raw survey answers are free to download as a spreadsheet.

By Ben Cohen and David Ng. Open it

Pairs with Candy Sweet 16Candy Report

1 chart, two questions

Which candy gives the most love per penny?

Each candy plotted by price and by love. The bargains jump right out.

FlowingData · Chart

Try this

Find a candy that is cheap but loved, and one that is pricey but unloved. If you were handing out candy on a budget, which corner of the chart would you shop from?

A data designer plotted the FiveThirtyEight candies by how much they cost and how much people love them, using candy names instead of dots. The good deals jump out.

By Nathan Yau. Open it

Pairs with Candy Report

2026 costume trends, live

Google’s live map of costume searches

What everyone is searching for this October, ranked by Google.

Google Frightgeist · Interactive

Try this

Pick one costume. Sketch the graph you’d expect for searches from September to December. When does it peak? Why does it crash?

Every October, Google’s Frightgeist ranks the costumes, movies and party ideas people are searching for most. Searches aren’t sales, but they move fast and they’re a fun first look at data.

By Google Trends. Open it

Also: Google’s 2026 trends post

Games & puzzles

Candy games with real math hiding inside.

1st player can always win

Chomp: the chocolate bar with one poisoned square

Whoever eats the poisoned corner loses. The first player can always win. On most bars, nobody knows how.

UCLA Math · Play online

Try this

Play on a 2-row bar until you find the winning move. Then try a square bar. (Big hint on Wikipedia, after you’ve tried.)

Take turns biting a chocolate bar. Each bite takes a square and everything above and to the right of it. Whoever eats the poisoned corner loses. Mathematicians proved the first player can always win, without being able to say how on most bars.

By Thomas S. Ferguson (UCLA). Open it

Also: How the proof works (Wikipedia)

NP-hard the class of the toughest puzzles

Candy Crush is officially hard

A computer scientist proved Candy Crush is as hard as the toughest puzzles in computing.

arXiv · Math paper

Try this

Read Smithsonian’s plain-English version first. Why can checking a winning set of moves be easy even when finding one is hard?

A computer scientist proved that winning a general Candy Crush board puts it in the same family as some of the hardest puzzles in computer science, like planning the best delivery routes.

By Toby Walsh. Open it

Also: Smithsonian’s plain-English version

2013 still free in a browser

Candy Box 2: a whole game about growing candy

A free text game where candy piles up every second. Spend it wisely.

Candy Box 2 · Free game

Try this

Keep a log: candy per second before and after each upgrade. How many seconds until an upgrade pays for itself? (Investors call that the payback period.)

A text-art adventure where candy piles up every second and you decide what to spend it on. It was made by a 19-year-old student in France and its code is open source.

By aniwey. Open it

Also: About the game (Wikipedia)

OCT 31 = DEC 25 really

Why math people mix up Halloween and Christmas

31 in base 8 equals 25 in base 10. That’s the whole joke, and it’s great.

The Big Apple · Math joke

Try this

Write 25 in base 16 and in base 2. Then invent your own joke: which date in base 16 equals a date in base 10?

Read “OCT” as octal (base 8) and “DEC” as decimal (base 10). 31 in base 8 is 3 eights plus 1, which is 25. Martin Gardner printed it in Scientific American back in 1966.

By Barry Popik. Open it

0 crayons needed to draw them

Halloween pictures drawn with equations

Pumpkins, cats and ghosts drawn with nothing but equations.

Desmos · Graphs to color

Try this

Open Desmos and draw a pumpkin: start with a circle, x² + y² = 25. How would you squash it wider? Add a stem with a line segment.

College students drew pumpkins, cats and ghosts using only equations in the free Desmos graphing calculator, then turned them into a coloring book for a kindergarten class.

By Luke Walsh’s students (Catawba Valley CC). Open it

Hidden history

Candy stories most grown-ups have never heard.

600 calories in one 4-ounce bar

The chocolate bar designed to taste bad

The Army asked for a bar that tasted “a little better than a boiled potato.”

Hershey Community Archives · Archive

Try this

A regular Hershey bar is about 1.55 ounces. How many would you need to match one Ration D bar’s 600 calories? Check the calories on a real wrapper.

In 1937 the Army asked Hershey for an emergency bar: about 4 ounces, able to handle heat, packed with energy, and tasting “just a little better than a boiled potato,” so soldiers would save it for emergencies.

By Hershey Community Archives. Open it

20% of M&M’s owned by the second M

M&M’s stands for two people, and one had 20%

The second M was Hershey’s president’s son. His share: 20%.

HISTORY · History

Try this

If a company made $1,000,000 profit, what would a 20% owner get? Why might Mars have wanted a partner connected to Hershey in 1941?

Forrest Mars started M&M’s in 1941 with Bruce Murrie, son of Hershey’s president, who got a 20% stake. During World War II they were sold only to the military. Mars later bought Murrie out.

By Laura Schumm. Open it

Pairs with Candy trends

9 billion kernels a year (2015 estimate)

Candy corn was first sold as “Chicken Feed”

Invented in the 1880s, sold in a box with a rooster on it.

National Geographic · History

Try this

Check the claim: 35 million pounds ÷ 9 billion kernels = how many grams per kernel? (1 pound ≈ 454 grams.) Weigh a real kernel on a kitchen scale. Close?

Candy corn dates to the 1880s and was sold in boxes with a rooster on the front. In 2015 the candy makers’ trade group put yearly production at about 35 million pounds, or roughly 9 billion kernels.

By Rebecca Rupp. Open it

Pairs with Log your haul

½ lb of sugar per person per week

The war that nearly ended trick-or-treating

Sugar was rationed to half a pound a week. Then Peanuts and Donald Duck helped bring trick-or-treating back.

HISTORY · History

Try this

Half a pound is about 227 grams. Read the grams of sugar on a fun-size wrapper. How many of those would one week’s ration cover?

Sugar was the first food rationed in World War II, cut to half a pound a week. Rationing ended in June 1947. Candy ads, a 1951 Peanuts strip and a 1952 Donald Duck cartoon helped bring trick-or-treating back big.

By Brynn Holland. Open it

Also: Halloween on the WWII home front

1 < 1 + 1 sometimes

Why a candy bar plus gum can feel worse than the bar alone

Kids who got a candy bar plus gum were less happy than kids who got just the bar.

NPR · Hidden Brain · Psychology

Try this

If you’re handing out candy, should the best piece go first or last? Run a tiny test with your family and see.

On Halloween night, Dartmouth researchers gave some trick-or-treaters a full-size bar and others the same bar plus a piece of gum. The kids who got the extra gum rated themselves less delighted. Endings shape how we remember things.

By Shankar Vedantam. Open it

Pairs with After the haul

Myth vs. math

Scary claims, checked with numbers.

0 confirmed cases of strangers harming trick-or-treaters this way

The poisoned-candy myth, checked for 60 years

A sociologist checked 60 years of reports. No confirmed case of a stranger’s candy seriously hurting a child.

The Counter · Research

Try this

Why can a story be everywhere but still be rare? Count how many times you’ve heard the warning versus how many real cases exist.

Sociologist Joel Best has checked news reports since the 1950s. He has found no substantiated case of a child killed or seriously hurt by a contaminated treat picked up while trick-or-treating. Scary stories spread faster than the corrections.

By Joe Fassler, on Joel Best’s research. Open it

about 4 extra deaths per Halloween, nationwide

“43% more” sounds scary. How many is that?

Cars are the real Halloween danger. Here’s how to read a scary percent.

Computational Complexity blog · Math blog

Try this

If 2.07 per hour is 43% more than 1.45 per hour, check the math. Then: what’s one change (light, reflective tape, a grown-up) that cuts the real risk?

A 2018 study found 43% more pedestrian deaths on Halloween evenings, and it’s real: cars are the actual Halloween danger. A computer scientist shows how a big percent can be a small number, and why both matter.

By Lance Fortnow. Open it

Also: The UBC study summary

Raw data to dig into yourself

The original spreadsheets behind the stories. Make your own chart, then compare with ours.

Quick answers

What is the best Halloween candy, according to data?

In FiveThirtyEight’s candy power ranking, built from about 269,000 head-to-head votes, Reese’s Peanut Butter Cups won 84% of their matchups, the top score. The Candy Hierarchy survey from UBC’s Science Creative Quarterly scores candy a different way, by JOY votes minus DESPAIR votes.

Sources: FiveThirtyEight (archived) · The Science Creative Quarterly (UBC)

How many licks does it take to get to the center of a Tootsie Pop?

It depends on who is licking. Tootsie Roll lists four studies: a Purdue licking machine averaged 364 licks, Purdue’s human volunteers averaged 252, a University of Michigan machine took 411, and Swarthmore junior high students averaged 144.

Sources: Tootsie

Has anyone really poisoned Halloween candy?

Sociologist Joel Best has tracked reports since the 1950s and found no substantiated case of a child killed or seriously hurt by a contaminated treat from a stranger while trick-or-treating. The bigger Halloween risk is traffic: a 2018 study found about 43% more pedestrian deaths on Halloween evenings.

Sources: The Counter · Computational Complexity blog

How many M&M’s fit in a jar?

Poured M&M’s fill about 68 to 71% of a container’s space, compared with about 64% for round balls (Princeton and Cornell physicists, Science, 2004). Estimate the jar’s volume, multiply by 0.7, and divide by the volume of one M&M.

Sources: Physics World · Wikipedia

Why do math people say Halloween equals Christmas?

Because OCT 31 = DEC 25. Read OCT as octal (base 8) and DEC as decimal (base 10): 31 in base 8 is 3 × 8 + 1 = 25. Martin Gardner printed the joke in Scientific American in 1966.

Sources: The Big Apple

Do kids who get more candy feel happier?

Not always. In a Dartmouth study on Halloween night, trick-or-treaters who got a full-size bar plus a piece of gum rated themselves less delighted than kids who got only the bar. People judge an experience heavily by how it ends.

Sources: NPR · Hidden Brain

How we pick

  • Real numbers. Every pick measures, counts or tests something. Every number on a card is from the linked page.
  • Made by people we can name. We credit the person or team behind each one.
  • Free to open. No sign-ups to read or play.
  • Checked by hand. We open every link before each update. Broken ones get an archived copy or come off the list.

Made something that belongs here, or found a broken link? Tell us at [email protected].