The “Janka” wood hardness scale

The Janka hardness test measures the resistance of a wood sample to denting and wear. It measures the force required to embed an 11.2 millimeter (0.444 inch) diameter ball halfway into the wood sample. A common use of Janka hardness ratings is to determine whether a species is suitable for use as wood flooring.

The chart is not to be considered an absolute; it is meant to help understand which woods are harder than others.