I live in a basement studio apartment. Does that mean I only have 1 room? (To calculate home office space.) I call my clients at my desk.

The bathroom is the only "room" I have in the studio.  Everything else, my bed, chairs and desks, kitchen, are all in the studio.  

Self-employed

You can also enter the size of the room (m² or ft²). Just make sure you use the same unit of measurement in the total area below.