This is an essential question as the best chainsaw bar for you must verify this criterion because you have to be sure that the product you're buying is the right size that fits your unit and the jobs you are going to use it in. The process of measuring a chainsaw bar is as follows: you simply take a measuring tape and calculate the distance from the place where the bar starts to be visible through the casing of the saw to the bar's tip, rounding it to the nearest integer. And there you go, now you have the correct length of your bar.