Given the modern style of this bed, we recommend the mattress does not exceed 22 cm in depth, to ensure the proportions are harmonious within the bedframe, as in the picture. However, if your mattress is deeper than 22 cm, (and max 27/28 cm deep) you can opt for the mattress insertion adapter, coming up on offer as you add the bed to the basket, which will lower the mattress by further 5 cm inside the bedframe, making sure the mattress does not sit too proud and cover the headboard excessively.