I'm trying to figure out how to ask where the toilets are if I'm in a restaurant. Of course I would start with '¿Dónde está...' but then I'm not sure whether to say 'lavabo', 'baño', 'servicios' or 'tocador'. Can all of these words be understood as 'toilets'? Which of them is the most formal and which is the most common?
Another very common alternative (in Spain at least) is ¿Dónde están los aseos? Since an aseo is basically a bathroom without the bathtub/shower, it could be considered more correct in a restaurant setting, etc. Having said that, ¿Dónde está el baño? or ¿Dónde están los servicios? would be universally understood and no one would think twice about it.