Floor-level open shower, what size?

Ours is 1.70 m wide and my architect said it can splash out there as well...

Splashing can also happen at 3m depending on what kind of shower head you have and how it is set...

However, with "normal" shower behavior and 1.5m it's probably the limit... we have 1.2m and a tile outside the shower occasionally gets wet... so about 30cm more.

I agree with mycraft. It can’t be perfect. We currently have a walk-in shower and the partition (glass) is at least 1.5m deep. Based on this experience, it shouldn’t be less. In front of the shower, we have a bath mat.

We are planning with just over 1.6m, possibly even a few centimeters more

We have 1.5m. Spraying out rarely happens there, but it still occurs, at least when using the Rainshower.

When I shower, it splashes about 1 - 1.20 m. When my wife showers, the 1.60 m of our shower are sometimes slightly exceeded as well ;)