Is midnight 12pm or 12am?

• EITHER, since it is both 12 hours before and after noon. The real question is: what is mid-day?

  John Hawthorne, Crawley, W Sussex.

• MIDNIGHT is 12pm. One must recognise the difference between points in time and periods of time. Midnight is the zero point in time when we start to build up 24 one-hour periods of time to make up a new day. So midnight is the point 0am. After a period of one hour we reach the point in time called 1am, and after 12 periods of one hour we reach the point called noon. At noon the 13th one-hour period starts, ending at point 1pm. This process continues up to the point 11pm when the 24th period of one hour starts. This period ends in the middle of the night, 12 hours after noon at the point midnight or 12pm.

  Geoff Berriman, Sandal, Wakefield.

• WHEN I was in the RAF 50 years ago this problem was solved by defining it out of existence. Working on the 24-hour clock meant that there was no difficulty with midday - 1200 hours - but the Air Force could not countenance 0000 hours for midnight. We were instructed that the Air Force day began at 0001 hours and ended at 2359 hours. The two minutes between were ours to use as we liked.

  James Eedle, Black Hill, Victoria, Australia.

• AS IS clear from consideration of the literal meanings of am and pm, noon is 12m, while 12am and 12pm have equal claims on midnight. We tend to avoid 12m nowadays from fear that someone may think m stands for midnight, but in avoiding this confusion we have been thrown into worse confusion by trying to determine which of 12am and 12pm to assign to noon and midnight.

  Ron Knight Chapel Hill, North Carolina, USA.

• EXACTLY one hour after 11 Post Meridiem comes 12 Post Meridiem. As it is dark then, I've always supposed it is midnight.

  Denis Buckley, Darwin, Australia.

• NEITHER, in the strict meaning of the words. But one minute after midnight (12.01) is unquestionably am. Hence for consistent usage, 12am must mean midnight.

  Adrian Pollock, Yardley, Pennsylvania.

• GEOFF BERRIMAN may be technically correct (which doesn't mean I'm agreeing with his strange theory), but in the real world he is wrong. Regardless of thoughts about points in time, 12.01, just after midnight is most definitely, and unarguably 12.01am. 12.01 just after noon is similarly 12.01pm. Also, an event that starts at 11.00pm and goes on until 11.01am has lasted over 12 hours, whereas an event that starts at 11.00pm and goes on until 11.01pm has lasted just one minute. This means that a meeting that starts at 12.00pm and goes on until 12.01pm must have lasted one minute (the alternative would give computer systems worldwide a bigger problem than the millennium bug). Therefore, 12.00pm must be at noon. QED. (Try booking some meetings, lunches etc at 12.00am and see the result.)

  Phil Benjamin, Enfield, Middx.

• WHEN I was in the RAF 50 years ago, this problem was solved by defining it out of existence. Working on the 24-hour clock meant that there was no difficulty with midday1200 hours - but the Air Force could not countenance 0000 hours for midnight. We were instructed that the Air Force day began at 0001 hours and ended at 2359 hours. The two minutes between were ours to use as we liked.

  James Eedle, Black Hill, Victoria, Australia.

• I am appaled at the rubbish I have read on this subject. There is no genuine confusion nor ambiguity only a self-made one. As the day begins at midnight, midnight must be 12am. The moment of noon is in the first second, consequently minute and hour of the afternoon therefore noon must be 12pm. It is poppycock to say that 12am and 12pm do not exist by considering the moments of noon and midnight within their own right - once the measures they belong to become clear, any supposed confusion vanishes.

  Mr Graham J Mayer, Epsom England

• Further to my previous comments, I am DISGUSTED at the ignorant statements that midnight has equal claims on AM and PM - HOW CAN MIDNIGHT BE PM OF A DAY TO WHICH IT DOES NOT BELONG - it MUST be 12am as it clearly belongs to a NEW day - the fact that the hour changes from ll.59pm (one minute before midnight) to 12.00 proves that the new hour must be either still in the same day or the new day - it MUST be the first hour of the new day, the previous day finishing at 11.59pm. in hour/minute language and ll.59.59pm in hour/minute/second language.

  Mr Graham James Mayer, Epsom England

• Further to my previous comments, I am DISGUSTED at the ignorant statements that midnight has equal claims on AM and PM - HOW CAN MIDNIGHT BE PM OF A DAY TO WHICH IT DOES NOT BELONG - it MUST be 12am as it clearly belongs to a NEW day - the fact that the hour changes from ll.59pm (one minute before midnight) to 12.00 proves that the new hour must be either still in the same day or the new day - it MUST be the first hour of the new day, the previous day finishing at 11.59pm. In hour/minute language and ll.59.59pm in hour/minute/second language.

  Mr Graham James Mayer, Epsom, England

• What a load of nonsense! 12am and 12pm are both mathmatically and logically inadmissable. 12 noon and 12 midnight are the only true values. However, for those who must use this notation, take a look at your digital clock dislay (12hr). When it changes to 12 noon it shows 12pm! And at midnight 12am! So for you freaks that must use an ambiguous notation surely this is the very thing. ie 12pm = noon 12am = midnight

  Bob Fisher, Rainham, Kent

• 12am and 12pm are both incorrect. Neither should be used. You should really pay attention to the abbreviation. "a.m." means "ante meridiem" which means "before midday" and p.m. means "post meridiem", which means "after midday". Consequently to use am/pm to refer to midday, (12noon) is simply wrong (and similarly midnight). The correct terms are 12 noon and 12 midnight, with times in between using am/pm.

  Colin Jones, Aberdeen, Scotland

• If midnight is 12am ('ANTE'= before 'MERIDIEM'= noon), then it follows logically that 1 hour later should be 11am, 2 hours later should be 10am, etc. Our current 11am would be 1am, closely followed by noon which would be 0am or 0pm (either - think 'noon' as in 'none'*). 1pm, 2pm, etc would be as now. Midnight would be 12am or 12pm (either). By counting forwards then backwards in time, we might stop getting older. *Actually 'noon' comes from 'nine' see www.etymonline.com :-D

  Phil Swallow, Lydbrook UK

• 12:00 is noon 24:00 is midnight

  John henschel, Surrey B.C. Canada

• WELL DONE! Absolutely the correct answer from Colin Jones, Aberdeen, Scotland. Why are poeple SO LAZY or ignorant that they need to avoid the use of 'noon or midday' and 'midnight' as CLEAR descriptions of time. Midnight needing to be qualified further as the end or beginning of a particular day. Worldwide adoption of 00.00 and 24.00 would help enormously!

  Stanley Sutcliffe, Halifax United Kingdom

• If we use the military time as our basis for this argument and for the sake of argument say that 2400 is midnight then we can simply answer this question using common sense math skills. Do we start counting at 12 or 24? No we don't. Do we believe that there is actually a time known as 00:00:00. Most people I know would say that this time does not exist or that doomsday is here if we were on that moment. Therefore the day begins with 00:00:01 (where we naturally start counting from). Using this argument I believe 12 noon to be 12am as it is the end of the morning. 12 midnight is 12pm or the end of the evening. If we take this to be true then we can see that military time as it is known uses 2400 because it is the end of that day and a full 24 hours otherwise why don't all of our clocks say 00:00:00.

  Michael Vandiver, Leeds, AL USA

• Let's look at a nasty example. My bank sent me a message this week asking me to pay in funds by 12pm on 12th June to avoid charges. I paid in at 3.07pm on 12th June and still got a charge because they say 3.07 pm is after 12pm! I called them and they have waived the charge, but still insist that 12pm is midday.

  John Griffiths, Norwich Norfolk

• Both 12am and 12pm are precise moments of time. 12am is the exact moment the 12th hour of the morning finishes (am), and similarly for pm. Therefor 12am is midday and pm would start straight after. The confusion has started since the invention of the digital clock.

  David Sulivan, Carshalton, Surrey

• My opinion: Midnight is neither 12pm nor 12am. Why? Well, I think of it this way: Midnight is an exact moment, the border, between the period of time after noon of the day ending (pm) and the period time before noon of the day beginning (am). I think of am and pm as periods of time between midday and midnight and not inclusive of them. An analogy would be the question: Is 5, >5 or <5? Of course it is neither. And though this concept is more obvious for noon, the same is true for midnight. When midnight strikes the digital clock is changing and the display says neither am or pm. So all you night owls, set your meetings for "12 midnight", "00.00" or if you must 12.00.01am.

  Alec Hendeson, Guildford, UK

• All this nonsense about using the terms 'mid-day' & 'mid-night' instead of A.M. or P.M is ridiculous. The argument that it is both ante and post midday does not hold. It is only both because you are using two days instead of the specific day you are talking about. 12am Monday is midnight Monday morning. It is A.M. (before mid-day Monday). To argue that it is also P.M (post mid-day) is irrelevant because it is only post mid-day Sunday not Monday. If you say 12am Monday there is no reason to confuse the P.M. of Sunday...this only adds to your confusion and ignorance.

  alex , Crawley UK

• My Opinion: 12 can be neither am nor pm. This applies to both 12s. I agree wholeheartedly with Alec Hendeson of Guildford UK and I think his analogy of <5 or >5 is relevant here. Is there an authority on the subject? I would refer readers to http://wwp.greenwichmeantime.com/info/noon.htm Is there a solution to all the confusion and differing opinions? Yes... Do as GMT suggests: Use 'noon' and 'midnight' or 12:00 and 23:59 & 00:01 instead of 12am/pm. At least there will be no confusion then.

  Jules Smibert, Gold Coast Australia

• As we normally count hours numerically adding 1 to the previous hour and as in a normal sequence 12 comes after 11 if it is then 11pm midnight must be 12pm and at the same time 00.00am so 1 minute past midnight is 00.01am the same applies to noon 11am being followed by 12am and at the same time being 00.00pm.

  Ian Jenks, Ampthill UK

• Alex, surely you could argue that the day does not start at 24:00? It starts at 00:00:01, which would mean that 12:00 would be 12am and then 24:00 would be 12pm. It depends how you classify a day, if it runs from 00:00:01 until 24:00:00 then 12am is noon and 12pm is midnight. If it runs from 00:00:00 until 23:59:59 then 12am is midnight and 12pm is noon, but surely we all agree 00:00:00 is not a time?

  Harris Boyle, Coventry UK

• Of course 00:00:00 is a time, it is one second before 00:00:01. Think how many computer operations could take place unnoticed in that no-man's land of a whole second second! 12:00pm Sunday night is the same time as 00:00am Monday morning. Just make sure you specify the appropriate day.

  Rob Corne, Auckland New Zealand

• Jules Smibert is correct. Midnight and midday are neither am or pm (as explained in the GMT link he provided). Basic calculus explains the concept well (see http://www.themathpage.com/acalc/infinity.htm). As 'x' approaches zero it never actually gets there just as it reciprocal never reaches infinity.

  Gary Reid, Wollongong Australia

• Midnight is neither 12pm or 12am, there is no such time. Midnight is 12 midnight and mid-day is 12 noon. All other usage is sloppy. As one reply says the armed forces use 23:59 and 00:01

  George Redgrave, Crawley United Kingdom

• The disagreement about midnight stems from the fact that it is a boundary between two days. 24:00:00 Monday and 00:00:00 Tuesday are both correct and both refer to the same moment. There is no reason to prefere one over the other except a desite for standardisation. Following this, it is obvious that this same moment in time can also be called 12pm Monday (because it is 12 hours after the Monday meridian) or 12am Tuesday (because it is 12 hours before the Tuesday meridian). The very fact that both of these positions can be defended is reason to never use either. Similarly, noon is the meridian and is therefor neither am nor pm. We only call it 12 o'clock because of the number on the dial. There is no logical reason why this number cannot be replaced with a zero.

  Yet Another Geek,

• I would refer you all to http://www.thaivisa.com/forum/topic/645370-12-am-and-12-pm/

  Jim Mills, Phuket Thailand

• 12 noon can be neither 12 am (in English before noon) nor 12 pm (after noon). It is simply noon. Since we do not notate time backwards, 12 midnight is not 12 am, since it would then require 1 am to become 11 am and so on. Similarly since it is the fleeting instant that marks both the end of one day and the beginning of the next (it belongs to both days and to neither),it is not 12 pm. In reality midnight has no sooner been reached than it has been passed. The phrase "the stroke of midnight" is apt. As has been demonstrated by many of the previous answers, and because it is incorrect, the use of 12 am and 12 pm is inherently confusing. To avoid this confusion it should be ended. The use of noon and midnight informally or 12 noon and 12 midnight or 1200 and 2400 should become practice.

  Bernard Maguire, Glasgow Scotland

• I have had fun reading all these answers. However, I have always held the fact that 12pm is noon. Example: Counting in minutes, you would have 10:58am, 10:59am, 11:00am, 11:01am etc. Therefore it stands to reason you would have: 11:58am, 11:59am, 12:00pm, 12:01pm. It would just be odd to have: 11:58am, 11:59am, 12:00am, 12:01pm ... e.g. 12:00am for simply 1 millisecond just doesn't make sense!

  John Wood, Sheffield, England

• Use 12 midday or 12 midnight for clarity. In my neck of the woods the usage is actually a logical counting up 9pm to 10pm to 11pm to 12pm ie counting up 12pm is MIDNIGHT 12 am is MIDDAY Fraction of a second do count logically 12 midnight is 12pm 12.00.01 is 12.00.01am It does of course depend on YOUR particular logic. It is easy to call others morons.

  T Brophy, St Helens UK

• Actually, Midnight is 12.00 AM (not 12.00 PM). Please read through the Clock System table in the below link: http://en.wikipedia.org/wiki/12-hour_clock

  Dilli Rajan, Chennai India

• It is very interesting reading all these comments. We need to realize that a clock gives us a means of reading time. Time is a fluid, always changing value. It is never what the clock says it is. Noon and midnight are for a infinitely small period of time as is any number on the clock represents. An example is the only clock that is correct is the one that is stopped. It gives the correct time twice a day. A running clock is always wrong. By the time we look at a clock that tells us it is noon, it is past noon and the same at midnight. So where does that leave us? When the time reaches noon, it is PM. When the time reaches midnight, it is AM. An analogue clock does not confuse, because our brain knows what it is telling us. The digital world we live in is trying to precise and yet it is not. To try to represent time in a digital way, we must realize that noon and midnight are only words. Our digital clocks should not say 12:00 AM or PM. The need to say midnight or noon. And the same goes for the written time. As one note said, when the clock say 12:00 and you see that it is dark out or, if you have not windows, you remember it was evening the last time to checked, it must be close to midnight not noon. Some common sense needs to be used somewhere in here. I personally will not wear the digital watch, because it gives me the false feeling that it is exact. I have never worn a watch that gives me the exact time.

  Bob Simons, Cameron, USA

• By technicality, mid-day and midnight exist for only a fraction of a second. By this assumption any time from 12:00:00:00:00:01 pm, (hour:minute:second:millisecond:microsecond:nanosecond notation) is after mid-day -I can't be bothered going smaller than that- 12pm, by this definition is "mid-day"

  Ben Wallace, Wellington, New Zealand

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