Door dimensions?

[Lurvnos]

I have started to tentatively explore the market for front doors, my current one is not exactly beautiful. But on all websites, I am only met with a cheerful recitation of 9x20, 10x20, 10x21 when I search for dimensions. I assume it's in decimeters, but is it exact? The door leaf or the frame? I have a gap in the house where the new door frame is supposed to fit. I assume there's a standard behind it, if anyone can give a tip, I would be happy.

 

[Immobil]

The dimensions given are module measurements in dm. They indicate how large the hole should be. The frame is then 15-20 mm smaller to fit into the hole.

 

[Lurvnos]

Thank you so much
It was that simple...