I wish there were quick and easy ways to do lots of things. I bet most people do.
I've been too lazy, or maybe not motivated enough, to get up and hunt for a ruler or measuring tape. I don't have one in the shopping bag I'm using for #yearofcrochetstitches and #yearofknitstitches. So how do i know if my squares are the right width? How do I know if they are actually square?
I know from years of gardening that I have 8" from thumb tip to pinky tip. This is the measurement my peas grew in double rows. Half of this is directed to me by the point of the between my index and middle finger. Try the measurements for your hands. Does it hold up for you?
Now, the quick and easy way to determine whether or not you have a square. Once you think it looks like a square, to be sure, fold it corner to corner so it forms a triangle. If the width matches the length, you have a winning square. Once you become comfortable with your own particular gauge, you can even start determining how many rows you have to knit or unknit.