Sleeping bag can be compressed down to the stuff size of 18x 10".
Yes it can be done. My best friend puts it inside his Cabela's Alaskan II backpack and still has ample room for our hunting trips. I use a medium size compression bag and then I put it inside a dry bag and pack with it on the outside and bottom of my pack frame.. It won't fit in a small bag like a "Cat's Meow" and it won't fit nicely under my backpack frame.. It's a little on the bigger side to pack, but it's warmer than my smaller "Cat's Meow" and it's worth the extra size. It still packs under the frame without a concern if you have good two compression straps. I hope this helps.