Room measurements

Hello, so I not too long ago acquired this flooring plan despatched to me for an residence. To my understanding a m² is a sq. of 1 meter by one meter so that will make the residence 52m by 52m. Nonetheless if you happen to see the doorways and the mattress or bathtub, assuming a tub could be 1.5m or perhaps 2m if we're hopeful and it could possibly match 5 instances on the wall (as soon as once more – hopeful), that will make zero sense? Am I simply dense or is the sqm measurement fully mistaken? Thanks!