How are flight hours counted? I was watching a presentation from a software developers' conference in which the presenter went through the steps leading to the crash of United Airlines Flight 232 to make a point about Crew Resource Management and how it relates to software development.
This prompted me to read the above linked Wikipedia article and see mentions of the flight hours the captain and first officer had accumulated. Now the Wikipedia article on flight hours doesn't explain it, so I was wondering: how are these flight hours logged (and I don't mean on which medium)?

Are fractions of an hour taken into account or only ever full hours? I.e. if some pilot flew 1:27 h on one flight and 1:33 h on another how does that count towards the logged flight hours?
Given many regulations surrounding aviation seem to be global, is the way flight hours are logged uniform around the world?
Any differences between commercial, private and military aviation?

NB: I'm a layperson.

Originally my question also asked for this detail:

Is the time from the gate to the runway counted?

In regard to US regulations it's been answered here
I can answer part of this by experience, as a non-professional hobbyist pilot, and partly by information which is fairly easy to come by. So here goes:

Are fractions of an hour taken into account or only ever full hours? I.e. if some pilot flew 1:27 h on one flight and 1:33 h on another how does that count towards the logged flight hours?

Fractions of hours are absolutely taken into account. Typically accuracy is not to the minute, as this would be fairly pointless but typical schemes are to round to the nearest 1/10th of an hour (6 minutes) or 5 minutes. Personally, a long time ago I chose to go for 5 minute rounding and have regretted it ever since - 6 minutes is much easier to add up when dealing with hours &amp; minutes!

Given many regulations surrounding aviation seem to be global, is the way flight hours are logged uniform around the world?

Nothing in aviation is global, or very little. Although there are bodies such as ICAO (International Civil Aviation Organisation) which most member states tend to derive most of their rules from. For the purpose of logging flight time, I expect most civil pilots log on the basis of &quot;Chock to chock&quot; time. Which is to say when the aircraft moves under it's own power until it stops.

Any differences between commercial, private and military aviation?

From what I can tell, the only difference is military which seem to log in-air time. This, I'm told, is why military airmen who intend to pursue a commercial pilot career after they're discharged maintain a separate record of their flight time.