The best-known toy brick maker is the LEGO company, which is based in Billund, Denmark (as of November 2026). The name LEGO comes from two Danish words, leg godt, which mean play well. The company started in 1932 as a small carpenter's shop in the village of Billund. Before it made plastic bricks, the shop made stepladders, ironing boards and wooden toys. LEGO did not invent the idea of a plastic brick, though. Kiddicraft, a British company, sold interlocking plastic bricks with studs before LEGO did.

A toy brick has bumps on top and is hollow underneath, so it snaps together. The grip comes from the studs on top, which fit tightly between the tubes inside another brick. Many toy bricks have tubes inside, but pieces that are only one stud wide use a thin bar instead. Bricks are built to be taken apart and built again. Old bricks can fit new bricks, because the brick has kept its design since 1958.

LEGO's first plastic bricks, from 1949, were called Automatic Binding Bricks. They had no tubes inside, so they did not hold together as well as later ones. In 1958 the tubes were added. They make the bricks grip each other, which LEGO calls clutch power, a word for how hard it is to pull two bricks apart. The man who thought of the tubes was Godtfred Kirk Christiansen, the son of the founder.

The plastic used for bricks is called ABS, which stands for acrylonitrile butadiene styrene. ABS is a thermoplastic: it softens when heated, so it can be melted, shaped in a mold and cooled hard again. It is also tough and strong enough to survive being dropped, which suits a toy. ABS can take any color and can have a glossy finish. Plastic was chosen for toys partly because it is easy to clean and comes in many colors and shapes.

Toy bricks are made from tiny plastic grains called granules. The granules are stored in giant tanks called silos and sent to the machines through tubes. In the big Billund plant, the silos fed the molding machines about 60 tons of plastic granules every 24 hours, a 2008 visitor reported. The main warehouse that held the silos was half a kilometer long.

Color is added at the machine, so one plastic can make bricks of many colors. Hot plastic is injected into one side of the mold, spreads through little channels and fills the brick-shaped space. Cold water flows through the mold to cool the plastic. Then the mold opens and the bricks drop onto a belt. Leftover plastic from the mold is ground up and used again almost right away.

Bricks that have faces or patterns get them printed or stamped on by machines. Machines also count the pieces that go into each box using light sensors. Pieces for sets are put into small bags, and the bags go into boxes that machines close. Machines weigh each box and bag, and any that are too light or too heavy are flagged so a person can check them.

Robots drive around the factory and carry boxes of new bricks. Few people work on the factory floor, where the bricks are made, because computers and machines handle most of the work. A big LEGO factory in Billund could make more than two million pieces every hour in 2008.

Almost all the plastic in a LEGO factory is reused: scrap from the molds, which is the plastic left over after the bricks are shaped, is ground up and fed back in, as a 2011 report found. Faulty pieces and the clear plastic used to flush a machine between colors are ground up and sold on.

Plastic that is thrown away does not rot away like food or paper. It can stay around for hundreds of years. Plastic made in the world grew from about two million tonnes in 1950 to more than 400 million tonnes a year (as of February 2026).

Most LEGO bricks are made of ABS, an oil-based plastic. LEGO says it is looking for other materials to use instead of ABS, and it says it wants to make its products from more sustainable materials by 2032. By 2023 it had tested more than 300 different materials. It estimates that about half (52 percent) of the raw material it bought to make bricks in 2025 was renewable or recycled, up from 33 percent in 2024, much of it counted by a mass-balance method.

Words to know

• granules: tiny plastic grains
• silos: giant storage tanks
• thermoplastic: plastic that melts
• studs: bumps on top
• clutch: grip strength