size in blender

hey guys i know we can model by using centimeters but i wonder how do you calculate the lenght of a kitchen ? for example when modeling is there somewhere you can get info of kitchens ? the space between the upper and lower cabins or how much they are in X and Y position ? also the size of a house wall how high should that be ? hope to get some help since i want to kinda try a realistich house :)