STEP 2: Measure your sheet You will need to
add several inches to your measurements to allow for seam allowances. For the sheet which will serve as the back of the duvet you will add 6″ to the length and 4″ to the width. For the front or top of your duvet you will simply add 4″ to both the length and the width. For instance my comforter measured at 84″x86″ so front/top of the cover at 88″x90″ and the back/bottom at 88″x92″. Cut your flat sheet to the appropriate length and width. Remember that this serves as the back/bottom of your cover and will need the additional 6″ in length and 4″ in width.