I have seen some people put their roll of batting on a wooden dowl and suspend it from the ceiling. Then they unroll it like pulling toilet paper off a roller and just cut straight across with scissors. My LA frame has a table on the back for laying out pantos. I store my roll underneath. When I want to cut it, I pull the roll out from the back of the table and pull off what I need and toss it over to the front (keeping the roll at the back) and measure what I need. Then I make a little cut on both sides. I line up those cuts on my back table and just run my scissors along the lip of the table aiming for the little cut on the opposite side. I have also cut with a rotary cutter but then I have to move the matt along underneath. Much easier to cut with scissors. I always cut generously, adding a few inches to be on the safe side. Usually I round up to the nearest 1/4 yard measurement. This just makes for easier record keeping of my batting inventory.