Well a yard of fabric isnt 36x36 inches. its 36x42 or thereabouts.
Connect6ingThreads in their *precuts* tells how many yards are in that package, for charms, jellyrolls, layercakes, and FQs.
If you want to use a pencil and paper, jellyrolls are 2.5 x width of fabric, charms are 5x5, layercakes are 10x10, and FQs, of course, are 18 x 21 inches, or so.....