The simplest fire pit designs are made from paving stones and sand. A common design is a circle of multiple layers of flat paving stones that use no extra types of material to hold them together. The ground within the circle is dug out and filled with sand, over which the fire is built.
This design can be made in multiple layouts, but the most typical ones are circular or rectangular. Basic versions of this style require little prior skill, extra tools or time. These can be improved and upgraded with other materials, such as fire glass, gas fire or fancy paving stones or bricks. To add stability, some include cement or other materials to ensure the stones do not move.
Other options include using metal walls instead of stone, such as sheet metal boxes or cylinders, upcycling old washing machine parts and recessing the pit further into the ground for a flatter addition to the outdoor area.
For more stability, the foundation can be made of concrete instead of sitting directly on the ground. Most locations have fire pit regulation codes, so new fire pits must meet these rules, such as being far enough away from the main home.