We manufacture our mattresses to metric sizes as below (for standard sizes):
Single: 90cm x 190cm (3ft x 6ft3)
Double: 135cm x 190cm (4ft6 x 6ft3)
King: 150cm x 200cm (5ft x 6ft6)
Superking: 180cm x 200cm (6ft x 6ft6)
In line with BS 1334:1996 , we have a +/- 20mm size tolerance on all mattresses and beds. In addition, many bed frames are still manufactured using imperial measurements (which are in brackets above). These imperial measurements are larger than the metric equivalent (so a “double imperial” frame would be 137cm x 191cm). If you have purchased an imperial frame with a metric mattress, the frame is likely to be bigger and therefore there may be a small gap. We believe that once bed linen is in place, this will be more than suitable.