I mean, I do read some articles about how to distinguish between those three, but I found that when I wrote stories or blog entries, the rules that I've read is impractical to remember. I found myself going over all the articles over again to decide which one to use, almost for every single sentence.

Can you give a very simple principal rule of thumb, which may cover a large portion of their usage rules? I understand that there's no single "one rule over them all", but at least "one rule over most of them", which I can remember while I write sentences, is already fine by me. :)


Here you have a lucky chance to get help from native speakers. I recommend you to read the answers using the link given above.

First of all you should learn that prepositions can belong to different groups (in,on,at can be used as prepositions of place and of time ).

As for place,roughly speaking, in means inside,on means on a surface,at means point where something or somebody is. But you should understand that everything depends on the context and there are lots of exceptions.

| improve this answer | |
  • I understand that in, on, and at can be used as prepositions of place and time, and there lies the problem. The one that always gets me confused is when using preposition for city. Like "I'm in New York" sounds normal, but "I'm at New York" also sounds normal too for me ("I'm on New York", by the way, sounds not normal). Or about time, "Let's meet at 3 o clock" sounds normal, but "Let's meet in 3 hours" also sounds normal. :( I have read the link above, and have get some better understanding, I think. I just hoped that I can feel that something is wrong if I used wrong preposition. :D – Chen Li Yong May 31 '16 at 1:23

In vs on vs at is something difficult for non-native speakers of English.

There isn't one simple principal rule. There are some general guidelines.

at indicates a particular point;

at home, at the bus stop, at 12:00pm, at 124 Main Steet

in indicates location inside;

in the house, in the park, in New York.

With times, in is used to refer to a later time;

"I'll be there in 3 hours"

Or periods of time or seasons

In May..., In the Summer..., In the last week of June...

on indicates surface location; e.g. on the road, on the chair. on is also used to specify something happens on a day.

"On Tuesday, We walked to the park."

Note that on is also used instead of in for most forms of public transportation (bus, train, plane).

We rode on the bus. We traveled on a plane.

In these sentences, the persons did not travel on the top surface of the vehicle as on would otherwise indicate.

| improve this answer | |
  • Oh, so in isn't used to describe something happens in a day. My native language describes that time is like a place, where you can describe position within time just like you describe position within a space. Sometimes I just confuse between "in 3 hours" and "on 3 o'clock". Thanks! – Chen Li Yong Jul 1 '16 at 3:05
  • "in a day" is like my "I'll be there in 3 hours" example. – eques Jul 1 '16 at 11:16

Not the answer you're looking for? Browse other questions tagged or ask your own question.