Width Roman blinds are a perfect choice for box-bay windows. As the material hides the mechanics of the blind, all you see is the fabric that you selected. By following this guide, the blinds will almost meet in the corners without overlapping, this means that all three blinds operate smoothly. 
When measuring, first of all take the measurements directly into the corners of the bay for both the front and the sides. For the width of the blind for the front, reduce the corner to corner measurement by 90mm (9cm), this will allow for the 45mm space that is required either side. For the widths of the side blinds, reduce the corner to corner measurement by 45mm (4.5cm).
 All three blinds would then be ordered as ‘exact fitting’ through our website.

Drop This is the same for all three blinds, even if you find that one window is longer than the others. This will ensure that when the roman blinds are lowered, they will all sit level. The measurement will be from the point where the blind is being mounted down to the window sill. Remember that you will need a flat space of at least 30mm (3cm) to mount the brackets securely. Measure the drop for all three windows and use the smallest of the three. 

Always check the widths in three places as you would for a regular recessed windows. Bay windows are prone to movement and you may find that the widths vary even if at first glance the windows look even. It is always the smallest of three measurements that you should be working with.