12.00am means midnight?

Yes, this is how it's done. I agree it's confusing. However: AM means *ante meridiem* ("before midday" in Latin) and PM means *post meridiem* ("after midday"). 12:00 of course *is* midday, so it doesn't really make sense for it to be AM or PM; however, as soon as we're past 12:00 (for example, 12:01) we are *after midday*, or "post meridiem" (PM). So for convenience's sake that one stray minute is also called PM, since the rest of the hour must be PM. To avoid confusion, many style guides suggest instead saying "twelve noon" and "twelve midnight". It's a similar concept to the 1800's being the nineteenth century and so forth. And I remember when Y2K happened, there were people saying, "Well, *actually*, the new millennium doesn't begin until 2001…" Edit: From the comments, it seems like you might be mistaken about how AM and PM are [used in Spanish](https://en.wikipedia.org/wiki/Date_and_time_notation_in_Spain#:~:text=There%20are%20no%20traditional%20suffixes%20for%20ante%20meridiem%20and%20post%20meridiem%20in%20Spanish%3B%20%22AM%22%20and%20%22PM%22%20are%20used%20when%20writing%20the%20time%20in%20the%2012%2Dhour%20format%2C%20in%20any%20of%20their%20variations%3A%20%22A.M./P.M.%22%2C%20%22a.m./p.m.%22%2C%20%22AM/PM%22%2C%20%22am/pm%22%2C%20%22a/p%22%20etc.%20The%20suffix%20for%20ante%20meridiem%20is%20often%20omitted%20completely).

Other comments are saying "in the US", but for the record, I'm almost certain that 12am=midnight is standard in all English speaking countries. 24-hour time, like what you're describing where 0:00=midnight, is also common.

In the US: \- 12:00 AM is midnight \- 12:01 AM is one minute after midnight \- 12:00 PM is noon \- 12:01 PM is one minute after noon

12am is midnight, 12pm is noon. But you can see the train ticket is trying to remove confusion by saying 12:01 Here in the US, PM starts at 12noon. AM starts at midnight (00:00). If you use 24 hour time here, people will know what you are talking about. Sometimes it is called military time since that’s where most people here use 24 hour time.

If this is pissing you off, I suggest you just steer clear of English. Actually, most languages will probably be an emotional minefield for you.

"PM" stands for "post meridiem", which literally means "after midday" (as opposed to "ante meridiem", or "before midday"). "Midday" is, as you say, 12.00. If "PM" started at 13.00, that would mean there was a whole hour between 12.00 and 13.00 which is after midday, but would be referred to as "before midday". I agree that the twelve-hour clock is potentially confusing, but insisting a full hour after "midday" is "before midday" seems *significantly* more so.

You will get lots of contradictory answers. People often argue about it. The truth is, there's no "correct" answer. There are various standards, but they differ. For that reason, it's best to avoid the problem. Make it absolutely clear what you mean. Call it midnight, or noon. Airlines do not have flights at 0:00 because too many people turn up on the wrong day. Instead, they deliberately schedule their flights at 23:59 or 0:01 instead. https://en.wikipedia.org/wiki/12-hour_clock#Confusion_at_noon_and_midnight

This is standard in the US and I believe in other English-speaking countries as well. It's a little confusing, but it makes sense if you think about it: AM is the first half of the day, from midnight to noon, and PM is the second half of the day, from noon to midnight. It wouldn't make sense to divide the day into 1am-1pm and 1pm-1am. I remember being confused by it too when I was a kid, but now that I'm used to it, it would confuse me if someone used 12am to mean noon or 12pm to mean midnight.

I don't know about every english speaking country, but, for sure the USA does.

PM means 'after midday'. If we are even 1 nanosecond (or less) after midday, then that's, by definition, PM. And then the way I see it is: * It would be weird if the moment of exact noon (12:00:00.0000000000000000...) was AM, but then a tiny fraction of a second after was was PM, because we'd display both of those as 12:00:00 on a clock with normal precision. * So we have to treat the exact moment of midday as PM as well for consistency.

Am=anti meridiem=before midday Pm=post meridiem=after midday 12:01 on its own may mean one or the other, but adding the “am” means it’s always in the morning/dark of night.

The RAE disagrees: > ¿Y para las 12 de la noche? En este caso se recomienda usar la abreviatura a. m., considerando que a medianoche comienza un nuevo día y, por tanto, su indicación horaria es anterior al mediodía de este: 12 a. m. [= doce de la noche].

1am is in the middle of the night, 1:01 am is 1 minute later, still in the middle of the night. If 12am was midday, it would be very confusing that 12:01am is almost 12 hours prior. The minute is made up of 60 seconds, technically it's only exactly midnight or midday for one second, but theres still another 59 seconds to describe, so the other 59 seconds in 12am would have to be in the am, so 12am is midnight

pm starts at 12:00 which is noon

You have 14 hours of am time and 10 hours of pm time, and you think we are the weird ones?

chiki en españa también usamos eso (??) 00 es 12am y 12 es 12pm ergo 13 es 1pm. En los ajustes del móvil te puedes cambiar la hora a la versión am/pm. A mi a veces me cuestan los numeritos, pq si son las 18 me cuesta decir que son las 6(pm) en vez de son las 18 horas

I'm sorry, but this is just complaining to complain, this is not even a weird quirk. Anything after the \*exact\* moment of midnight is AM until the \*exact\* moment of 12 noon. If 12:01 is PM, why in the world would 12:00 not be PM also. PM starting at 13:00 is literally misunderstanding what AM/PM refers to — the meridians, which (we've decided) are at 12:00 and 24:00

You are mistaken. "P.M." means *post meridiem*, while "A.M." means *ante meridiem*. "Meridiem" is the Latin word for "noon", so *post meridiem* means "after noon", while *ante meridiem* means "before noon". The expressions "12 A.M." and "12 P.M." are not really correct, since "12" can be either midnight or noon, but noon doesn't occur before or after itself. Thus, the better terms would be "12 noon" or "12 midnight." However, once the moment of noon has passed, then **anything** after it and before midnight is correctly called "P.M.", while anything after midnight and before noon is called "A.M." Thus, even just one second after noon is correctly written as 12:00:01 P.M. It is illogical to think that the hour that follows noon is somehow not really *post meridiem* (= after noon), and it is equally incorrect to think that a train that departs one minute after midnight is not really leaving at a time before noon -- that is, a time that is *ante meridiem.*

Twelve noon is when PM begins. After 11:59 PM, one minute to midnight changes to 12:00 midnight, that is 12:00 AM.

Yes! AM Stands for Ante Meridium which means before midday. PM means after midday They teach AM/PM in First grade . In Spanish midnight is doce de la mañana, same thing basically -12 in the morning

I think it's because conceptually it's the morning for you until la hora de comer. But yeah, AM is before noon, literally.

Just to say, that ticket starting at 12:01 AM is done specifically to allay this sort of confusion. Lots of places with starting times at either noon or midnight will start one minute "late" so that even if someone has a different understanding of AM/PM, it will likely stop them from immediately assuming it's one or the other and more carefully identify the actual time. Although I guess it wouldn't necessarily help that much if you really don't count PM until 13:00. Are you sure that's actually the case, or maybe just because it's used rarely in your country that you haven't encountered a lot of 12:15 PM appointments?

Yes, that's just how it works. It makes sense because 12:00 is the start of the hour. Hence 12:01AM is just after 12:00AM. And 12:01PM is just after 12:00PM. It would be more confusing the other way around, I think.

Why does other countries having different conventions “piss you off”? Does it make you mad that other countries drive on the other side of the road or use metric/imperial? Do you throw a tantrum when you order a “pint” and it’s not the size you’re expecting?

no, 1200 is NOT "am" 1200am is "am" and 1200 is not 1200am either you use "am and pm" or you use military time either you have 0000-2359 or you have 1200am-1159am, 1200pm-1159pm don't mix them

Think about it in terms of the analog clock. The clock face is numbered 1-12, with 12 being the point where you switch between A.M. and P.M. A.M. is everything from midnight to noon, so yes midnight is 12 A.M. and then we go around the clock until we hit 12 again and switch to P.M. at noon. All that considered, you typically don't need to specify am or pm when actually speaking English, as the majority of the time context will imply which half of the day you're referring to. Things like plane/train tickets will obviously be different cause some of them run all day, but most people aren't going to say 'hey let's do something after work, meet me around 6pm?' cause 'after work' will already imply a pm timeframe and also 6am would be a ridiculous time to offer to go out and do most things.

I’m pretty sure almost every country does it like this

You're wrong. 12 am is 00:00 in Spain as well. P.m. always start at 12:00, not 13:00 hs. You just never learned it for some reason, but it's common knowledge.