I don't know and i am glad you asked as i would like to know. thanks for asking hope some one will let us know.

I'd like to know, too.

I wonder*

They advise max. 20% when you are sticking to the same stitch count. If you can resize and maintain the stitch density, there are no hard and fast rules. BUT enlarging a small design may show up irregularities in the design (curved lines may turn into multiple straight stretches - outlines may be off - fillings skip corners) and decreasing the size of a large design may result in too many finicky details. So it's just a matter of trying and having a critical look at the result, first in your software and if that looks okay in the test stitch-out.

As Martine said, if you're doing it on your machine, or in another 'sizing' program, 10 or 20% max. If you have actual digitizing software that changes the stitch count, you can play more. But it doesn't always work like you think it should, even then. Always always test before you do anything good with designs that have been re-sized. Hugs, Marji

The others have given you the answer, except don't re-size FSL. If you must, never go smaller and always test stitch on organza or tuil if you try going larger.