How do I measure off the shelf curtains?

[IbizaToTheNorfolkBroads]

Do the width measurements for these curtains mean
width per individual curtain?
width per pair of curtains?
width of curtain track?

here

Width will be per curtain.

If you click on product description on the JL site, then scroll right down, it has this info to help you get the right size.

I alway buy 90 x 90.

Then they’re nice and full and reach the floor.

(Or 228 x 228 in centimetres.)

The width they show is per curtain.

If they are pencil pleat then you want each curtain to be about the same width as your pole so that they look nicely gathered.

So if your pole is 168cm wide then you want curtains that are 168cm wide because when you put 2 curtains on the pole the total width of the curtains will mean that even when they are closed they will still look gathered.

You can go for a bit less width with eyelet curtains but you still want some gather so they aren't pulled totally flat when they are closed.

Brilliant.
Thank you.
@IdWantThatManInMyLifeboat I feel a bit stupid for not finding that critical piece of info.
@InfoSecInTheCity that's what I thought, but wasn't 100% sure.