What is the Marshmallow Challenge?

The Marshmallow Challenge is a team building activity in which small teams have 18 minutes to build the tallest possible free-standing structure using 20 sticks of spaghetti, one yard of tape, one yard of string and one marshmallow — which must sit on top. The tallest standing tower with the marshmallow on top wins.

What are the rules of the Marshmallow Challenge?

The whole marshmallow must be on top of the structure, the tower must stand on its own when time is called, and teams may use only the supplied spaghetti, tape and string. They can break the spaghetti and cut the tape and string, but nothing may be taped or anchored to the table. Height is measured from the table to the bottom of the marshmallow.

Why do kindergarteners beat business school graduates at the Marshmallow Challenge?

Kindergarteners build a series of quick prototypes with the marshmallow on top from the start, so they discover early that it is heavier than it looks. MBA students spend most of their time planning and jockeying for status, then place the marshmallow at the last minute — only to watch the tower collapse. The lesson is that early prototyping and testing beats elaborate planning.

How many people should be on a Marshmallow Challenge team?

Three to six people per team works best. Fewer than three limits collaboration, and more than six leaves people standing around with nothing to do. If you have a large group, split into several teams of four or five and run all the towers at once so everyone stays hands-on.

What does the Marshmallow Challenge teach teams?

It teaches iterative prototyping, testing assumptions early, and the danger of over-planning. It also surfaces how a team handles time pressure, hidden assumptions, leadership and communication — which is why it is a favorite experiential learning exercise for kicking off collaboration or problem-solving conversations.

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Activity guide

The Marshmallow Challenge

Eighteen minutes, 20 sticks of spaghetti and one marshmallow — the deceptively simple build that teaches teams more about prototyping and collaboration than a day of slides ever could.

By James Carter, founder of Building Teams — 25+ years designing team-building experiences for hundreds of leadership teams. Updated July 2026.

The Marshmallow Challenge is one of the most widely run team building activities in the world, and for good reason: it takes 18 minutes, costs almost nothing, and teaches a lesson about how teams actually work that people remember long after the spaghetti is swept up. The premise is simple. Give each team 20 sticks of uncooked spaghetti, one yard of masking tape, one yard of string and a single marshmallow. In 18 minutes, they have to build the tallest free-standing structure they can — with the whole marshmallow sitting on top. The tallest standing tower wins.

What makes it a great exercise isn’t the tower. It’s what the build reveals about a team’s instincts under pressure. This is experiential learning at its most efficient: people don’t hear about collaboration and prototyping, they live through it, then unpack what happened. Below is how to run it well and how to get the real value out of the debrief.

What the Marshmallow Challenge is

Each team of three to six people receives an identical kit: 20 sticks of dry spaghetti, one yard (about 90 cm) of tape, one yard of string and one standard-size marshmallow. The goal is height — measured from the tabletop to the bottom of the marshmallow — and the structure must stand on its own when the facilitator calls time. The marshmallow has to be on top, whole and uncut. Teams can break the spaghetti and cut the tape and string however they like, but nothing may be anchored or taped to the table, the ceiling or a chair. If the tower topples before time is called, that team scores zero.

How to run it

You need almost nothing to run this activity, which is part of its charm.

Materials per team: 20 sticks of spaghetti, 1 yard of masking tape, 1 yard of string, 1 marshmallow, and a tape measure or ruler for judging. Have a few spare marshmallows on hand — they get squashed.
Group size: Three to six people per team is the sweet spot. Larger crowds simply split into more teams, all building at once, so nobody is watching from the sidelines.
Time: Set a visible 18-minute countdown and hold to it strictly — the time pressure is the point. Add five minutes at the start to explain the rules and five to ten minutes at the end to measure, celebrate the winner and debrief.
Space: One table per team with room to move around it. That’s it.

Read the rules aloud, confirm everyone understands that the whole marshmallow goes on top, start the clock, and resist the urge to help. Call out the time remaining at the halfway mark, at five minutes and in the final 30 seconds — watching a room realize its tower can’t hold the marshmallow with ten seconds left is the whole show.

The famous lesson: why kindergarteners beat MBAs

The Marshmallow Challenge became famous because of a counterintuitive result popularized by designer Tom Wujec: recent business-school graduates are among the worst performers, while kindergarteners routinely build taller, more stable structures. It sounds like a joke, but the reason is a genuine lesson in how teams create.

MBA students tend to treat the task as a planning problem. They spend most of the 18 minutes talking, sketching, agreeing on the one right design and quietly jockeying for who’s in charge. Then, with a minute or two left, they place the marshmallow on top for the first time — and discover it’s far heavier than the spaghetti can bear. The tower buckles, and there’s no time left to recover. Kindergarteners do the opposite. They start building almost immediately, they put the marshmallow on top from the very first attempt, and when a version sags they simply try another one. By the time the clock runs out they’ve tested five or six prototypes and kept whatever stood.

The takeaway is the heart of the debrief: prototyping beats planning. The teams that test their riskiest assumption early — here, that a marshmallow is light — find out the truth while there’s still time to respond. The teams that plan a perfect solution on paper only meet reality when it’s too late. It’s the same reason iterative, hands-on approaches outperform big up-front designs in real product and project work.

What to watch for as a facilitator

Pay attention to how each team spends its first three minutes. The strong ones start building and testing right away; the ones in trouble are still debating. Notice who takes charge, whether anyone tests the marshmallow’s weight before the end, and how teams react when a structure fails — do they iterate calmly or panic? These are the observations that make your debrief specific and honest rather than generic. Also watch for the team that quietly reads the rules most carefully; there is nothing that says the marshmallow can’t be pushed onto the spaghetti to distribute the load, and clever reading of constraints is itself worth naming.

Debrief questions

The build is nothing without the conversation afterward. Some questions that reliably open it up:

When did your team first put the marshmallow on top — and what happened when you did?
How much time did you spend planning versus building? Would you change that balance?
What assumption turned out to be wrong, and when did you discover it?
Who ended up leading, and was that decided or did it just happen?
Where else in our work do we plan a perfect solution before testing the risky part?

Variations

Once a group knows the standard version, you can raise the stakes. Run a second round immediately — scores almost always jump, which proves the value of iteration in a single sitting. Add an “incentive” round with a prize to show how high stakes can make teams more cautious and conservative. Introduce a mid-build “market change” where you hand out an extra constraint at the nine-minute mark. Or run a silent version where teams can’t speak, forcing them to communicate through the build itself. Each twist surfaces a different facet of how your team collaborates.

Bring the lesson to your team

The Marshmallow Challenge is a perfect opener for a workshop on iteration, collaboration or innovation — and it pairs naturally with deeper problem-solving activities. If you want a facilitator to run it and connect the lesson to how your team actually works, or you’re looking for more formats to run yourself, browse the activity library. When you’re ready, tell us your goals and we’ll design a session around them.

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