Right- it all depends how much fullness you want- i like a lot.
I'm not metric, so my window is 88", which is just over 2 yards, and i bought 6 yards of fabric, so that would be triple the width of the window, give or take xx
No less than double the width in my opinion.Anything less just looks like you bought them for smaller windows as it is difficult to get the gathering to look right.
...............or expect to wash them every week............mind you I wash mine weekly and I only smoke outside.I can't stand to walk past houses and see really grubby or nicotine stained nets in the windows
I am a little obsessive about nets Bathsheba due to the fact my mum smokes heavily indooors and never takes the nets down to wash them.I decided to help her out once and wash them for her and was absolutely ,gut- wrenchingly disgusted at the colour of the water in the washing machine as they were washing.It was brown because of the nicotine YUCK!!!
I haven't had nets for years, as all the cats we've had, kept jumping up at any insects on them & they eventually became clawed & never looked straight!
When I did have them, I used to by 2.5 times the width.
I've got different types of *net* in my house - in the front of the house I've got cotton Victorian style (these are 2x the window width) but at the back I've got cotton drapes from Ikea and because they are very simple and plain, I've got them at 1.5x the width otherwise they obscure too much light and look too heavy. If you're thinking of putting up polyester nets then 2x or 2.5x would be good, it really depends on how *full* you want them to look. It used to be that 2x was the optimum with 1.5x if you were a bit brassed... but I think it more depends on the look you are trying to achieve and how much light you want in those rooms (my neighbour has got very simple drapes in fine muslin with no gather whatsoever and they look great !)
PS What sort of window frames have you got ? If they are pvc, then post again and I'll give you some hints on easy ways to hang nets on pvc windows lol....