It is also hard to put an exact estimate on the cost of adding a new bathroom as this would depend on the size of the room, the facilities, and the quality of the fittings, and materials. Many bathrooms act as steam rooms, contain hot tubs, or are installed with underfloor heating – Luxury additions such as this can significantly increase the overall cost.
As such, the cost of a second bathroom can range between $3000, up to $25000, or more.
As your additional bathroom will likely involve the conversion of a normal room, rather than the renovation of an existing bathroom, costs such as new plumbing and electrical layouts can also be a big percentage of your budget.