The finished shade width. Include molding in width for external mounting. 3-inch (77.2 mm) is automatically added to facing material for edge finishing. 2-inch (50.8 mm) is added to the lining fabric.

The finished shade height. Not including top and bottom hems.

Actual width of fabric (often 46, 54, or 60 inches -- 1168, 1372, and 1524 mm)

The width of the battens that will be inserted in each slat pocket. Usually between .75 to 4 inches (8 to 100 mm).

Total number of shades with these dimensions.

The vertical repeat of a patterned fabric. Needed if quantity is greater than one or curtain width exceeds fabric width. Decimals are permitted.

A rough indication of the desired depth of the top-most fold in the shade--the "valance". The actual depth of this fold as well as the total stack height of the retracted shade will vary due to rounding and depending upon battens and hardware used. The calculated default is our recommendation (we think that it will result in the best looking shade -- the best balance between height and fold depth) but it can be modified if desired.