# How to write untidy fractional hours

Let's say I traveled for 6 hours and 40 min. How should I write that?

6 hours and 40 min

or

6.40 hours

or

6.40 min

or

6h.40 min

• Where are you writing this / for what purpose? Are you writing something scientific / formal/ informal etc? – amblina Jun 22 '15 at 13:38
• Regarding close votes: "If it is 6 hours and 40 minutes how to write " This question is not answered at the link provided. – Adam Jun 22 '15 at 16:51
• "6 hours and 30 min." or "six and a half hours". "half hours" only works when it is 30 min., so "6 hours and 40 min." – user3169 Jun 22 '15 at 17:49

My suggestion is to write them in the way that most clearly communicates what you are trying to say. If you are informing someone of how long your trip took, 6 hours (and) 40 minutes is fine. If it's clear from the context that it is a duration you could write 6:40, but this can be unclear whether you are referring to a time of day, minutes and seconds, or hours and minutes, so I wouldn't recommend it.

If you are comparing durations, 6.67 hours could be the best choice. For example, if you were comparing the times to finish a task, and one person completed it in 6.67 hours and a second person completed it in 6.72 hours. This is usual for academic or scientific writing and unusual for general writing.

The preferred way depends on the context, but in general the way that is clearest is to spell it out as 6 hours and 40 minutes.

• Writing digits inline like "I traveled for 6 hours and 40 minutes" looks awkward, since small numbers like 6 should be written as words in such cases. And then "six hours and 40 minutes" looks odd too. Otherwise we appear to largely agree. ;) – Nathan Tuggy Jun 22 '15 at 20:24
• @Nathan I agree it's a little awkward, and I usually will drop the "and" between the hours and minutes. I don't think I hold too closely to the "spell it out if the number is small" rule though. I tend to prefer consistency. If I'm not going to spell out forty, I won't spell out six in the same sentence. – ColleenV Jun 22 '15 at 21:09
• Well, yes, but my instinct would tend to push me the other way: if I'm spelling out six, I'm not going to spell out forty. :P – Nathan Tuggy Jun 22 '15 at 21:11

In English, parts of time are conventionally separated by colons (`:`). If it's clear that you're talking about a fairly large amount of time (i.e., not minutes:seconds), you can use that without any other notation:

The flight took 6:40, so I'm pretty tired.

Or to be a little more easily pronounceable, you can use h and m:

The flight took 6h40m, so I'm pretty tired.

This is similar to the example you gave of "6h.40 min", but shorter.

If you want to spell it out more, at the cost of more words, there's not really anything wrong with putting everything in:

The flight took six hours and forty minutes, so I'm pretty tired.

(Here, you should not use the digit 6, by convention — it's small enough [less than 10 or so] and being used as a word inline in a sentence, rather than a digit in a number — and therefore writing 40 in digits looks awkward next to it, so it should be avoided as well.)

"6:40 hours" isn't especially ambiguous, but it's unusual and (to my California eye) looks weird — pronouncing it aloud or mentally leads to backtracking in order to get the right meaning. It's probably best to avoid this.

In "6:40 min", nobody will be sure whether you mean hours:minutes or minutes:seconds, so it's not only awkward, but ambiguous. Avoid at all costs.

Strictly speaking, the last example you gave works as written, especially in a more scientific context. But unless you're very clearly writing nothing but decimal numbers, it's a dangerous formulation in general, since other quantities like "6.20 hours" are ambiguous: did you mean 6.2000000 hours, or 6 hours and 20 minutes? (Especially if your writing suggests English is a second language, since other languages often use other delimiters for time, dates, etc.)

• Your point about mixing digits and words looking awkward is under-appreciated, so +1 for that. Another possibility is to round because people don’t need high precision in most time contexts. For example, if your flight takes 2h 34m 56s, everybody is going to call that two and a half hours, so here it would be more like six and three-quarters hours. It easier to understand that way. – tchrist Jan 7 '18 at 14:50