With the explanation on the website, even when the wood I wanted to use (wenge in one case) wasn't listed, it was easy to google the coefficients, use the formula, and figure out how much I needed to allow for wood movement here in Calgary. For the great price of free too!
After several minutes of familiarizing myself with the data, I applied it to my latest project built during winter and forecasting wood movement midsummer and pleased to learn it is minimal. Very easily accommodated with threaded inserts in oversized holes. My only wish is that it had curly maple listed, but used the others listed similar hardness.
This simple chart is really handy for determining the space needed for expansion/contraction of your projects. And it's free?
This is a valuable resource for professionals and hobbyists alike and I'm glad I found it.
Very handy piece of work - takes a lot of the unpredictability out of working with wood.