Wooden blocks come in all shapes and varieties. However, when you break it down, they really can be categorized into three types. These three types are:

1. Unit Blocks
2. Tabletop Blocks
3. and ABC Blocks

Unit Blocks

This is the type of wooden blocks that everyone thinks of when you say “wooden blocks.” These blocks are found in most day-cares and kindergartens and are also known as Kindergarten blocks (or kindergarden blocks for those who are spelling impaired like me). The picture to the right shows a “unit” with a “unit arch” proped on it. These block sets are standardized to a certain size. No matter who makes them, they should be compatible. The unit block is always 1 3/8″ x 2 3/4″ x 5 1/2″. You will notice that all of these dimensions are proportional so stacking them will always work as long as you get the right number of blocks in there. All of the block sizes are built off of the unit block. For example the double unit block is 1 3/8″ x 2 3/4″ x 11″. There are about 30 different standard shapes that are available in unit blocks. Most sets do not have all of the shapes.

Table Top Blocks

There is nothing standard about table top blocks. The only thing that is the same with these sets is that they are smaller than the kindergarten blocks. Some are exactly 1/2 unit block size. Most are not. There are no standard shapes, and they don’t tend to go together with different manufacturer’s sets. However, they can be an awful lot of fun as some of the shapes can be pretty unique!

ABC Wooden Blocks

Like the table top blocks, A-B-C Wooden Blocks are not standard. They come in all sizes, types of wood, and design. Some are carved and brightly painted, others have their pictures silkscreened or painted on. Some of the older or more classic sets are real works of art. One thing these sets do have in common is they tend to be cubes, they will have the letters a-z, and often have numbers and pictures on them.