Just prepare a dummy with materials corresponding to the final specs… And measure the hell out of that.

> Can gsm be converted in to millimeters of thickness?

Not directly. The bulk of paper will depend as much upon the density of the fibers, not just the weight. You’d need to get your printer or paper supplier to provide the caliper or ppi specs for your particular sheet.

But since this is a student project, and probably a one-off, Bert’s suggestion is probably easiest: trial and error ;-)

> probably no more than ten pages...
> I was thinking saddle-stitch

Perhaps you already know this, but you can't have a 10-page saddle-stitched piece. Must be in multiples of 4.

2 sheets of paper folded and saddle-stitched become 8 pages, 3 sheets become 12, and so forth.

"Small-ish" is a rather imprecise term. Practically speaking, something like 5"×8½"—or half a standard letter-size sheet—would be easy and cheap to produce: three sheets for the content and one for the cover. I offered a 5" width to solve your creep problem: simply face-trim the book to the 5" width after it's assembled and there's no worry about having your slip showing.

@Bert: Good idea, I'll give that a shot.

@Kentlew: You're right, this is a one off, and I'm not even sure which paper stock I'm using yet.

@JamesM: I hadn't thought of that! Thanks for pointing that out, you've saved me a lot of time.

@Oldnick: True, since the last post I've started planning my designs for an A5-sized booklet so that shouldn't be a problem. All I need to do is find some suitable paper-stock for the cover.

Thanks for your help guys!