What blade size do I actually need?

7-1/4 inch is the universal standard and handles dimensional lumber up to 2x material at 45 degrees. Step up to 8-1/4 inch (SKILSAW SPT78W) for deeper single-pass cuts in thicker stock, or to the 16-5/16 inch SawSquatch for beams and timbers. Mini 4-1/2 inch saws are a separate category aimed at trim, plywood and one-handed work, not framing.