We've designed The Marshmallow Bed to work with Australian standard mattress sizes, and is currently available in 3 sizes below. We use a standard mattress height of 28cm in all of our product photos. All mattress heights will work, however, please note, larger mattresses will cover up more of the headboard. Double - 138 x 190cm Queen - 153 x 203cm King - 183 x 203cm