If you're looking to purchase hardwood flooring, you're likely to run into something called the Janka Hardness Scale. The Janka Hardness Scale is used to measure the hardness of a wood. More specifically, the test measures the force required to push a steel ball with a diameter of 11.28 millimeters (0.444 inches) into the wood to a depth of half the ball's diameter. The diameter was chosen to produce a circle with an area of 100 square millimeters.

The higher a wood's Janka rating, the harder - and generally more durable - the wood will be. While the softer Eastern White Pine is a mere 380 on the Janka Scale, Ipe (sometimes referred to as Brazilian Walnut) ranks at a much harder 3680. Red Oak is often referenced as the middle point of the scale with a Janka rating around 1280.

When shopping for hardwood flooring you should consider where the floor will be located in your home and how much traffic it will get. While the Janka Hardness Scale should play a role in your decision, it should not be the only factor you look at when purchasing a hardwood floor. You should choose a wood with a texture, grain, and color that fits your style.