Both floor pillows I made are 32" squares, and that is massive. My 3 year old is dwarfed by it so I know that it will be very useful for years to come. Any larger than that and you're honestly giving up a lot of valuable floor space. Just keep that in mind.
The second thing I wanted to mention is the fiber fill itself. I highly recommend that in the interest of cost savings, DO NOT go to a craft store like Joanns or Hobby Lobby for the filling, because you will pay a fortune (I learned this the hard way). At 32", these pillows require about 100 oz of filling each. This number sounds useless, but trust me, the poly fill bags will have an ounce amount on them. The original filling I bought was a bag at 40 oz for a whopping $20 each at Joanns! Yikes! Sorry, but that's the whole reason I DIY--to make things on the cheap. The stuffing part of the pillow shouldn't be that much. So I went to Walmart and found a 50 oz poly fill bag for $7.44. I can handle that so much better. So there's my two cents on the stuffing amount and cost.
Happy sewing!
