Machinist’s calipers offer woodworkers a solid tool for measuring exactly how big a tenon or mortise to make. By taking away the guesswork as you sneak up on a perfect fit, you’ll work more efficiently, cranking out solid joinery with tight tolerances more easily. The same goes for dadoes, rabbets, and a whole host of other joints.

The benefits of machinist’s calipers, as well as a step-by-step tutorial on how to use calipers, can be found in furniture maker Timothy Rousseau‘s Fine Woodworking magazine article on the subject. To make life a bit easier, we’ve cobbled together a simple-to-use fraction-to-decimal conversion chart. Download it for free, post it in your shop, and get to work.

Download the Fraction-to-Decimal Conversion Chart