# What is the correct way to write 1.5 hours?

I'm a bit confused in describing 1.5hrs in words.

Is writing one and a half an hour correct or should it be one and half hour?

E.g:

I'll see you there in one and a half an hour.

OR

I'll see you there in one and half hour.

Or is there any other correct way of writing this?

• Since none of the answers actually addresses this directly, focusing instead on alternative ways of expressing a 90-minute span, I’ll just mention briefly here that the main point of this question, whether one and half hour without the article before half works, can be answered very simple: no. Half here is being used as a predeterminer, which means that it always requires a determiner (article, possessive determiner, etc.) to be present, too. You cannot have a predeterminer without a determiner. – Janus Bahs Jacquet Jan 31 '15 at 15:53

In general, for some number of hours, plus some fraction of an hour, you'd use the number, plus the fraction, plus "hours", plural. "Four and a half hours.", "Three and three-quarters hours," etc.

However, for the specific case of 1.5 hours, the usual expression is "an hour and a half". This usage is so common that "One and a half hours" actually sounds strange.

• Agreed. We also say, "See you in 90 minutes". – Tᴚoɯɐuo Jan 30 '15 at 12:10
• True that we often say "an hour and a half". But that works for other fractions too: "an hour and a quarter" for example. I don't think "one and a half hours" sounds strange at all; people say that all the time. I think both are equally acceptable. – Jay Jan 30 '15 at 14:16
• ...and conversationally it's common to hear "an hour [number]" such as "an hour fifteen" instead of "an hour and fifteen minutes" or "an hour twenty" instead of "an hour and twenty minutes". – zzzzBov Jan 30 '15 at 17:33
• In which country? – Brian Hitchcock Jan 31 '15 at 16:52
• Agreed, however "One and a half hours" doesn't sound strange 9as in wrong) so much as slightly unusual (in that you're not using the expected phrase). Note also that "an hour 15" and "an hour 20" are very much American English expressions: they would sound very strange (or just plain wrong) to British English speakers – Jon Story Dec 30 '15 at 11:55

One and a half hours

English is a bit strange, if I'm talking about exactly one hour, then I say hour and not hours. For every other number, I use plural. This applies to every noun in the English language that has a plural tense:

1. I have one dollar
2. I have zero dollars
3. I have 1.1 dollars
4. I have -1 dollars
• ...partly true, partly misleading: in the case of unit fractions (1/2, 1/4 etc.) you do technically refer to one hour as part of the phrase, but strictly speaking they are other numbers for which you don't use a plural - half an hour, a quarter of an hour etc, although decimalizing switches it back over - 0.5 hours, 0.25 hours etc. A clumsy but grammatically correct alternative for the OPs example would be: one hour plus half an hour. – bruised reed Jan 30 '15 at 11:41
• @bruisedreed I'm not trying to be pedantic, but your example involving fractions doesn't contradict my answer or prove it to be "partly misleading". Saying "half an hour" grammatically means one half of one hour, while saying "zero point five hours" refers to 0.5 hours. I also think it's poor form to encourage an English learner to say "one hour plus half an hour" which isn't used in everyday English. – Mark Jan 30 '15 at 11:50
• Okay, let's put it this way: For exactly one, we use the singular: "one hour". For more than one, we use the plural: "two hours". For a fraction, you can say "of an hour", like "half of an hour", "three quarters of an hour", etc. That's how we usually say it if we use a ratio-type fraction. For half we sometimes omit the "of" and simply say "half an hour", but I don't think that works with any other fraction: no one says "a quarter an hour" or "three-fifths an hour". ... – Jay Jan 30 '15 at 14:12
• @Jay Weird— as a native AmE speaker, if I see it written 1.0 h, I'll probably say one point zero hours, not one point zero hour. – Paul Senzee Jan 30 '15 at 19:02
• @PaulSenzee I'd say "one point zero hours" also. Probably because we're used to using the plural when there's a decimal point, even though it's another way of saying "one". Just like, if it was an expression, I'd likely use the plural even if it came out to 1. Like, "Hmm, so the time comes out to .4 plus .6 hours". Certainly in a case like, "The time required is x times 2 minus 3 hours, and x is equal to 2." – Jay Feb 2 '15 at 6:45

I love hearing how English-as-a-second-language persons construct phrases like this! It's so fun. I can completely understand what they are trying to say, but marvel at how they construct the idea in a way that makes sense to them, but would be unusual for a native English speaker.

Here are some ways native English speakers would describe time:

Very common:

• "an hour and a half"

• "one and a half hours"

• "an hour and thirty minutes"

common:

• "ninety minutes"

somewhat less common:

• "one hour and thirty minutes"

uncommon:

• "one hour, thirty minutes"

not used:

• "one hour, and one half hour"

• "the sum of an hour and half of an hour"

• "one hour, plus an additional half hour"

• "two hours minus one half hour"

• "seventy-five percent of two hours"

Basically, if it sounds like a math equation, it's probably not used!

You can always get out of this conundrum by writing:

An hour and a half

or:

90 minutes

Other answers discuss writing the quantity as words. When writing things as numerals, however, I would suggest that the decimal fraction .5 as being a perfectly good way of indicating "half". For partial-hour quantities other than 30 minutes, I would avoid other decimal fractions unless times are being measured in six-minute or 36-second intervals, but .5 is so idiomatic as "one half" that I would consider "1.5 hours" to be more readable than "1 hour and 30 minutes" or "1 1/2 hours", or even "1½ hours".

• You may be right. But the OP clearly states says "I'm a bit confused in describing 1.5hrs in words". – Varun Nair Dec 30 '15 at 12:12

My interpretation of the debate would be "two and a half hours" VS "two and one half hours". The latter was taught in grade school. Toss the fraction in as you wish.