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Which K’nex building sets are best?

K’nex are educational construction and building sets that use interlocking plastic rods and connectors to build models, machines and architectural structures. Because the many different pieces are able to interlock in different directions and at different angles, the number of possible creations is endless.

K’nex helps kids develop their fine motor skills and learn to solve problems. If you are looking for a K’nex building set that teaches kids about motion, propulsion, acceleration and velocity while they play, take a look at the K’nex Education STEM Explorations Vehicle Building Set.

What to know before you buy a K’nex building set

K’nex has building toys designed for all age groups and skill levels. Kids assemble their model by looking at the pictures, finding the pieces in their set that match in shape, size and color and clicking them together. All pieces of the same size and shape come in the same color. Instructions include piece-by-piece photos alongside easily understandable text.  


K’nex rods come in many different lengths and degrees of flexibility. Rods come in rigid, slightly flexible and very flexible versions to create different shapes. 


K’nex connectors link rods together. Connectors are also color-coded and have anywhere from two to more than a dozen ways to connect rods.

What to look for in a quality K’nex building set

K’nex makes five different categories of building sets. Take a quick look at each so that you can choose a model that is age-appropriate for your child.


This series is designed for kids five and older. Core building sets are for kids who want an easy building experience. Choose from sets that build motorcycles, jeeps, dragsters, helicopters, jumbo jets, space shuttles, dune buggies and more.

Thrill rides 

K'nex 6 foot tall working ferris wheel

Choose from many different roller coaster building sets, including Pac-Man, Shark Attack, Dragon’s Revenge and Bionic Blast. If you are looking for a truly incredible challenge for a child that is already an expert builder, take a look at the K’nex 6 foot tall working ferris wheel with more than 8,000 parts. 


Kids can build authentic replicas of the Eiffel Tower, Golden Gate Bridge or London Eye. Each set comes with color-coded, step-by-step instructions and the history of the landmark.


K’nex Education sets are used in classrooms everywhere. Parents who like playing and learning alongside their kids buy education sets for use at home. Choose from a wide variety of topics, including Renewable Energy, DNA Replication & Transcription, Bridge Structures, Gears, Levers & Pulleys, Wheels, Axles & Inclined Planes and Simple Machines.

Kid K’nex

The Kid K’nex line is built for little hands. Kid K’nex building sets have larger, brightly colored pieces that are made of softer materials. Little kids click the pieces together to build planes, trains, outlandish and fanciful creatures and more.

How much you can expect to spend on a K’nex building set

Small, non-motorized K’nex building sets cost as little as $10. From $25–$50 you will find complex designs with motors and more pieces. K’nex sets with thousands of pieces cost anywhere from $100 and up.

K’nex building sets FAQ

Are K’nex and LEGO the same thing?

A. LEGOs use hard blocks to form solid structures with fewer moving parts than K’nex. K’nex parts and structures have more flexibility that allows for greater freedom of design.

Can Kids K’nex building sets be used with regular K’nex?

A. No, they are separate systems. The sets made for kids under five have bigger and softer pieces that are easier for small hands to pick up and play with.

What are the best K’nex building sets to buy?

Top K’nex building sets 

K'nex Education STEM Explorations Vehicle Building Set

K’nex Education STEM Explorations Vehicle Building Set

What you need to know: Made for kids eight and up, this K’nex building set includes 130 parts that build seven different powered vehicles.

What you’ll love: Kids learn about potential and kinetic energy, motion, acceleration, velocity and more. Kids use this K’nex building set to build vehicles with different power sources, like rubber bands, springs, wind power and the simple push-pull. This building set is aligned to US National STEM standards and is appropriate for kids in third, fourth and fifth grade.

What you should consider: After kids build these vehicles, they can use them to conduct hands-on, inquiry-based experiments.

Where to buy: Sold by Amazon

Top K’nex building set for the money

kid K'nex 66 Piece Build a Bunch Set

Kid K’nex 66 Piece Build a Bunch Set

What you need to know: This K’nex set is designed for kids ages 3-5 to learn the basic concepts of building while they are playing.

What you’ll love: The 66 pieces in this Kid K’nex building set stack, plug and snap to make 30 different models, including cars, airplanes, bugs, animals and sci-fi creatures.

What you should consider: Some children wished the wheels rolled, a feature that comes in all the full-sized K’nex building sets.

Where to buy: Sold by Amazon

Worth checking out

K'nex Thrill Rides Bionic Blast 809 Piece Roller Coaster Building Set

K’nex Thrill Rides Bionic Blast 809 Piece Roller Coaster Building Set

What you need to know: Kids ages seven and up can ride the roller coaster they built themselves in virtual reality with the free K’nex Ride It! app.

What you’ll love: Kids follow the color coded instructions that lead them step-by-step until all 809 pieces are in place. This K’nex building set for kids includes coaster tracks, a car and the motor. The motor drives the ferris wheels to lift the car to the top of the roller coaster track and gravity takes over as the car rushes down the track, through the loops and around the curves. 

What you should consider: The required AA batteries are not included.

Where to buy: Sold by Amazon


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David Allan Van writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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