I'm german. if it's completely unambiguous, we simply say "dinner is at 6" or "my shift ends at 4". but when you want to make sure that there's no room for confusion we say "let's meet at 21 o'clock".

I'm Dutch. Usually we just say something like "2 in the afternoon" instead of 14:00 or 2 PM. But digital clocks and writing etc will use 24 hours. Every now and then people will use it though, saying 14:30 as "fourteen hours thirty", but that's quite rare and sounds a bit formal (or goofy).

In French, it's pretty common to say 14 o'clock.

I'm a nurse who uses 24-hr time at work and it's about 50/50 with me saying "fourteen hundred" or "2pm" when speaking. I generally find that my colleagues understand both and use both interchangeably.

They say fourteen hundred or 2 o'clock. I've never really heard anyone say 14 o'clock.

In Denmark we say "2 o'clock" or just "14", sometimes also "14 o'clock". No one says fourteen hundred, except perhaps for a few military wannabes.

If it's quarter past 2, we'd usually say "14-15". Half past 2 would be "14-30", you get the idea.

If we mean to say "from 2 o'clock to 3 o'clock", we'll say "14 to 15", which I imagine can be confusing for the uninitiated, as the only difference from "quarter past 2" would be a "to".

For those downvoting me, what do you say? I imagine it must be other Danes or neighboring countries, as one surely wouldn't downvote a culturally dependant statement if not from said culture.

I basically always write the time as a four-figure number, and verbally refer to 1400 as "two o'clock", "two in the afternoon" etc. in English but "viertien uur" or "twee uur" in Dutch.

Edit: I used to work in a train station in the UK, and we'd always say train times as (one- or two-figure number)(0 like "o" if it's there)(one- or two-figure number). So 1400 is fourteen-o-o, 1407 is fourteen-o-seven, 1412 is fourteen twelve, 0502 is five-o-two. Among staff, we'd refer to them just by the minutes, so the o-two, the seventeen, the forty-eight, etc.

1400 (fourteen hundred)