The dimension of a wood-fired pizza oven will vary greatly. It all depends on the intended purpose of the pizza oven. If you need an oven that is not limited to cooking pizza, then a large pizza is good. However, if you need a pizza-only oven or for other home based small foods, then the standard 32" x 36" (82 cm x 92 cm) oven is sufficient. This is the foundation size and the dome width should be ¾ of the foundation size. The foundation should laid 20 cm from the ground, and the height of the entry door should be 10 inch (25.4 cm) and the height of the vault (internal): 16 inch (40.6 cm).

Further information: How to build a pizza oven and Wood Fired Pizza Oven Building Plans