There are all kinds of ways of expressing times and writing them down, but the commonest formats in English aren’t the same as the usual Dutch ones.
Dutch authors come up with all kinds of variants, mostly because they would write it in their own language with some extra word to show it’s a time, unlike English. So for half past five, I regularly see things like 17h30, 17.30 hrs, 5.30h pm, 17hrs 30, 5H30 PM and many others. Normal and acceptable time formats include:
- with a colon and nothing else, 08:30 or 17:50
- you’ll get away with dots instead of colons, though it’s less common
- twelve-hour notation rather than twenty-four, 8:30 AM or 5:50 PM
- although there’s no hard and fast rule, people mostly use leading zeroes if needed for 24-hour notations but not for 12-hour forms
- am, a.m. and AM all get used. I’m no fan of AM/PM, mind, given that everyone knows 24-hour formats nowadays and midday/midnight aren’t clear
- Don’t add the word hours or any abbreviation for it anywhere. It wouldn’t be said out loud (except in the military) and it adds nothing.
You’re unlikely to cause confusion, unless you pick a particularly obscure format (the film title above is apparently American military jargon for half past midnight). But some of the ones listed above will stand out quickly as non-native.
Prevalence: moderate. Opening hours on websites are a great source of wacky representations.
Frequency: high. In particular, Dutch writers tend to feel that they’ve got to do something with the word uur, rather than just leaving it out.
Native: no. There’s quite some variability, but only specific formats.