I'm making a baby quilt, well 2 actually, one boy one girl, for my hope chest, but I used half of a 24 piece jelly roll on each so they're a little small and to make it bigger, I'm adding borders. But I don't know how big to make the outer border so that it's a good size. Unfinished with one border already on it's 28 by 36. I can't get a good pic of it to post but the inner border is 2 inches wide.

When I was a new mom years and years ago I like a bigger quilt so I could wrap my little one up in the colder weather. The ones I am making for my hope chest are almost lap size quilts instead of crib size.

I just googled standard cribsize quilts. 45 X 60 inches

You could even add 2 more borders. Make first 2-1/2" and the last 3-1/2". If adding just one more border I would do at least 5". Either would give you a pretty good size quilt that would last many years. Lap size is usually a minimum 45"x60" (or least that is what I use). Good luck.

I used warm & natural craft size batting (36x46) on one I recently completed & it seems ok to me.
http://www.quiltingboard.com/t-132786-1.htm

Knowing that my daughter (25) still sleeps with her baby quilt... I always try and make mine a little larger than normal. But go with what makes you happy!

It depends on what size quilt you are wanting and what it will be used for.

If you want a pretty little quilt to wrap baby in to bring him/her home from the hospital, or to tuck around baby in the car seat/stroller, a small one this size is perfect for a infant.

If you are talking about a quilt that will be big enough to be useful for a few years or more a crib size would be better.

Depends on use...crib 45x60; wrap a baby 40x40 is good.