Cutting loft insulation when still wrapped - is it the same width when unrolled?

[Plexie]

Hope I can explain this clearly.

There's lots of advice online to cut rolls of loft insulation to the required width while it's still wrapped and compressed. But I seem to remember reading a while ago that the compressed insulation is slightly squashed out width-ways when wrapped, and that it 'shrinks' back to its intended width when it's unwrapped. So when you cut the roll you'd need to cut slightly wider to allow for the shrinkage.

However there are now loads of reviews from people saying how easy it is to cut the correct width and no mention of the width shrinking. Am I worrying about nothing? Or perhaps the advice I read was about old-style insulation.

Basically, if I were to cut a 30cm strip while it was still wrapped, would it still be 30cm wide after I unwrap it or would it 'shrink' to less than 30cm wide?

It's the Knauf Ekoroll I'm referring to, if that makes a difference.

TIA.

I seem to remember it coming with perforations every 30cm or so and you could more or less tear it apart at that width. Probably worth checking that first. I've only done it a couple of times and my memory is that it's not a terribly precise job anyway and you end up with loads of bits and pieces that you can tuck down the side if you have cut it too narrow. Why not try cutting one length unrolled at 30cm and seeing how it fits and taking it from there?

Due to the way the insulation is manufactured it will not shrink width wise when cut, only slightly in thickness due to the compression.

As its flexible you can cut is a few cm over the required 30cm anyway and squeeze it in. That will eliminate any gaps