Below are listed the relative hardness for numerous wood species used in flooring. The higher the number the harder the wood. These ratings were determined using the Janka Hardness Test.

The Janka (or side) hardness test measures the force required to embed a .444 inch steel ball to half its diameter in wood. This is one of the best measures of the ability of wood species to withstand denting and wear. It is also a good indicator of how hard a species is to saw or nail. 

This should only be used as a general guide when comparing various species of wood flooring. Depending on where the wood is harvested the results may vary + or -. Plank construction and finish are also important factors when determining the durability and ease of maintenance of any wood floor.