[click here to see a Janka chart]

Janka Hardness Ratings

The Janka, or “side,” hardness rating of wood is a relative measurement of its resistance to impact and wear. Therefore, the rating gives prospective flooring buyers a numerical representation of the wood’s durability. This is obviously very important for matching flooring material to its intended usage. Higher levels of foot traffic would require a more durable species and thus one with a higher Janka rating.

The Janka test basically involves measuring the amount of force, in pounds per square inch (psi), required to embed half the diameter of a 0.444-inch steel ball into the face of a wood sample. Of course, several tests are performed to find the proper amount of force, and then a series of tests are averaged to determine the rating. Technically, the average includes samples of tangential (plain-sawn) and radial (quarter-sawn) material.

To give you a comparison between a popular domestic and a popular exotic hardwood, let’s look at Northern red oak and Jatoba (aka Brazilian cherry). If you have ever worked with red oak, then you are familiar with how it cuts and nails. Its Janka rating is 1290. Jatoba, on the other hand, has a Janka rating of 2820 – that’s 119% harder!