Difference Between On & At

What Does On Mean?
On is a preposition that can indicate a specific time as well as a location. When referring to time, we use on with dates. For example,
He went to Paris on Sunday.
The office is closed on Saturdays.
I usually visit the temple on my birthday.
Figure 01: On can indicate a Date or a Day
When referring to a place, we use on with:
– a position on any surface
Her wallet is on the table.
She sat on the big double bed.
– a position along a road or river or by the sea or by a lake
Galle is a major city on the southern coast of Sri Lanka.

What Does At Mean?
At is a preposition that indicates a specific time as well as a specific place. We can use at with particular points on the clock as well as particular points in the day or week. For example,
They went to the cemetery at midnight.
What are you doing at the weekend?
Figure 01: At refers to a Specific Time
When referring to a location, we use this preposition to:
– refer to a position or location which is seen as a point
He was sitting at my desk, when I entered the office.
– refer to locations at companies, workplaces (those seen as places of activities)
Do you know how many people work at Facebook, Inc.?
– to refer to an address
We once lived at number 12, South Chando Street.
Further, when compared to the preposition in, which also indicates time and location, at  indicates more specific times and locations.

Key Takeaways

• On is used to talk about days and dates, while at is used to talk about specific times.
• On can refer to a position on any surface or along a road, river, or coastline, while at refers to a position seen as a point, locations at companies, workplaces, and addresses.
• At generally indicates a more specific time and location than on.