If you mean square feet to square metres, then there are 10.764 sq.feet to a square metre. So, however many square feet you have, divide it by 10.764 and that's the equivalent in sq.metres. Dividing by 10 is easier if you just need a rough idea! Converting sq.metres to sq.feet is the opposite - ie. multiply your sq.metres by 10.764 to get the area in square feet. Cheers