12am & 12pm – What’s the difference?!
12 o’clock: we all know there are two a day – one at lunchtime and one at night – but which one is 12am and which one is 12pm?
That’s what we’ll be looking at in this article. We will also see some other useful words and phrases that can crop up when we need to tell the time, or ask what the time is.
So what is am & pm?
First of all, what do am and pm actually mean? Both come from Latin originally:
am = ante meridiem (between midnight and midday)
pm = post meridiem (between midday and midnight)
So returning to the question about the difference between 8am and 8pm:
8am is in the morning, and
8pm is in the evening.
OK, but what if someone talks about something happening at midnight on Tuesday? Is that 12am or 12pm. Is it the night between Monday and Tuesday or between Tuesday and Wednesday ?
Midnight and midday
Some will say midnight is 12am, and therefore that midday (or noon) is 12pm. Others will say this doesn’t make sense as noon can be neither am (before noon) or pm (after noon)!
When we talk about midnight last night or midnight tonight, the meaning is clear ; but less so when we talk about, for example, midnight on Sunday. Is that at the beginning or at the end of Sunday?!
There is some debate about this so it’s better to be clear from the outset, for example:
I should be home by midnight Saturday night.
The last bus arrives just before midnight on Friday nights.
12-hour clock or 24-hour clock?
In English, do we use the 12-hour clock or 24-hour clock ? In other words, do we say for example 2pm or 14:00 ?
In general conversations and situations in English, we use the 12-hour clock format. In practice, that means counting the hours from 1 to 12 in the morning and in the afternoon. More often than not, it’s clear if we are talking about the morning or the afternoon. Let’s look at a few examples:
I usually have breakfast at about 6:30 – we have breakfast in the morning.
We’ve got a team meeting at 2:15 – a team meeting implies a work situation, people do work shifts but we can be reasonably sure it’s in the afternoon.
The film starts at 7:45 – films are usually shown in the afternoons and evenings so it’s 7:45pm.
Sometimes, such sentences can be unclear :
His plane leaves at 8:15.
Is that am or pm ? Planes leave at both those times. It’s clearer to say something like :
His plane leaves at 8:15 tomorrow morning.
They’ll be arriving at about 7:30 Friday evening.
Some other key vocabulary
To finish, here are some key words (highlighted in bold) that can be useful when telling the time, some of which we’ve already seen :
I eat in the morning / afternoon / evening.
They sleep at night.
We arrived just before / just after 8 o’clock.
What time is it ? It’s almost 10 o’clock.
I should arrive at about / around 7:30.
Owen Vickery moved to France upon graduation in the UK. In English teaching for 20 years & author of 2 books, he contributes to a site for learning English & specialises in writing online content.
Yes, you might wonder: “Is it midnight at the start of Sunday or at the end of Sunday?” BUT, look at the word “midNIGHT”. Midnight is in the MIDdle of the NIGHT, not in the MIDdle of the DAY! Sunday NIGHT runs from 6pm (Sunday evening) to 6am (Monday morning). So “midnight on Sunday” is at the end of Sunday, not at the start. Check out Day and Night:
That’s a very good point! Midnight on Sunday is confusing.
Formal documents (contracts, agreements…) may well clarify by saying something like 23:59 or 00:01 to get around this question.
We can also say “midnight Sunday morning” or “midnight Sunday night” to clarify.
sheldon Li says:
Thank you but I am more confused after reading this article because I still don’t know how to understand “the midnight on sunday”.
David Martín says:
@Uni you’re an early bird 😉
It’s 9:43am in Spain.
I commented at 5:27 in the morning.
Thank you so much.
Thanks.Very useful explanation
Hamza Haji Abagidi says:
Thank you very much for goodgiving us this good explanation for the difference.