Question about weeks pregnant


Weird question. So when you (or someone) say how far along you are to the general world (aka not 4 weeks 3 days) do you say 4 weeks or 5?

What I mean is, Glow is saying I’m 4 weeks pregnant but when I read their “on this day” what it is saying matches more with the 5 weeks then 4. So I know that technically I’m in my 5th week of pregnancy but I’ve only completed 4.

But if I want to do a week by week photo would I say that I was 5 or 4 weeks?