All Queen size beds are 60x80....that is the top of the bed,,,so why not add 36 inches to the 60" width and add 18" to the 80" length...you should be ok with this size......and don't worry about being a perfect size for this particular bed....they won't have that bed forever....I have been making bed spreads and duvet covers for 15 yrs.....and unless they will use the quilt for a bedspread I would use the standard 60x80 size with a little hangover on sides.....hope this helps