The limiting factor is probably 1. the battery capacity and 2. the water tanks in wipe mode. However, it can recharge and continue where it left off, but that takes a relatively long time.

Our flat is just under 150m2, (minus furniture) 2/3 of which is slab flooring which I always have mopped as well. It takes 100 minutes and the battery charge is still over 40%.

Does that help?

Does not matter
The unit makes a measurement automatically at the beginning.