Grammar Clinic: The REAL difference Between IN, ON and AT

The one part of speech that even experienced writers easily find confusing is preposition.

More often than not, either IN or ON or AT can be grammatically correct. It entirely depends what you really mean in your statements.

Hints

A) It is advisable to use ON to denote a position for surfaces or a position just above or outside an area. Example:

1. The pen is placed on the table.
2. Ola has a mole on her face.

B) Use IN when you are indicating a position for spaces with limitations. IN is used to convey that something is contained or inside. For example,

1. My mum is in Lagos.
2. The file is in the disk.

C) At could mean at a SPECIFIC POINT or at a general location. For Example,

1. Turn right at the next traffic light.
2. I’m at school (Not necessarily within the school premises).

D) IN is used to denote a moment enclosed in time. It is therefore used with other parts of the day, with months, with years, with seasons. Some examples of these are,

1.  I like to drink water early in the morning.
2. My brother’s wedding is in October.

E) ON is used with days and dates. Also, it may be used in special parts of the day and special holidays. Distinctively, ON is used when you do not enclose something.

1. I’ll see you on Friday!
2. We look for colourful eggs on Easter Sunday.

There are some special considerations of using these three prepositions and it would be best to learn them from experience.

Summary

1. IN is used when you are referring to something enclosed by limitations while ON is relatively specific and does not denote anything enclosed.
2. Besides being used for a specific location, ‘At’ is more general. It gives an approximate location regarding a key landmark and is usually used for large locations such as buildings. It can also be used for events, such as ‘I’m at the music festival’. You would never say ‘I’m in the music festival’ unless you were playing the music on stage!
3. IN is used to denote a location of something inside a space while ON generally, denotes something above a surface or within proximity.
4. Whether it is used with place or time, normally, IN is general as compared to the specific implications of ON.