Grammar rule and drill

Prepositions of time and place: at, on and in

At, on and in for clock times, days and periods, and for points, surfaces and spaces.

CEFR A2-B120 questionsUpdated 5 October 2026

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At, on and in do two jobs each: one for time and one for place. Learners worry about them because the rules feel random. They are not random, but they do change shape between time and place.

For time, think of size: at is a point on the clock, on is a day or a date, in is a longer box such as a month, a season or a year. For place, think of shape: at is a point, on is a surface or a line, in is an enclosed space.

This page covers both jobs, adds for, since, during, by and until, and finishes with 20 questions that mix time and place.

The rule

Time: at, on and in by size

At plus a clock time, a mealtime or a point in the day: at seven o'clock, at noon, at lunchtime, at midnight, at night.
On plus a day or a date: on Monday, on Friday morning, on 5 May, on my birthday, on New Year's Day.
In plus a longer box: in October, in 2026, in summer, in the morning, in the afternoon, in the evening.
The pattern by size: at (a point), on (a day), in (a period).

Other time prepositions

For plus a length of time: for three hours, for two weeks, for a long time.
Since plus a starting point: since Monday, since 2020, since I was a child.
During plus a noun that names a period: during the film, during the summer, during the meeting.
By means not later than: "Finish the report by Friday." Until means up to that time: "I worked until midnight."
In plus a future length of time means at the end of it: "The train leaves in ten minutes."

Place: at, on and in by shape

At plus a point or a building you are visiting: at the door, at the bus stop, at the station, at home, at school, at work.
On plus a surface or a line: on the table, on the wall, on the floor, on the bus, on the train, on the second floor.
In plus an enclosed space or an area: in the room, in the car, in London, in Spain, in the sea, in the middle.
At the corner (British) and on the corner (American) are both correct in their variety.

Fixed pairs worth memorising

At home, at work, at school, at university, at the airport, at the party.
In bed, in hospital, in prison, in the car, in the park, in town.
On the bus, on the train, on the plane, on a bike, on the left, on the internet, on the phone.
Arrive in a city or country, arrive at a building or event: arrive in Paris, arrive at the hotel.
A few pairs change meaning: in the corner of a room, but on the corner of a street.

Examples

The meeting starts at 9:30 on Tuesday.At for the clock time, on for the day.
We go to Italy in July.In for a month, a season or a year.
I will see you on Friday morning.On with day plus part of the day.
She has worked here for six months.For with a length of time.
She has worked here since January.Since with a starting point.
Please send the file by Monday.By means not later than Monday.
He waited at the bus stop.At for a point in space.
Your keys are on the kitchen table.On for a surface.
The children are in the garden.In for an enclosed or defined area.
We arrived in Rome at midnight.Arrive in for a city; at for a clock time.

Common mistakes

Wrong: The class starts in Monday. Right: The class starts on Monday.: Days and dates take on, even when the sentence also has a clock time.
Wrong: I drink coffee at the morning. Right: I drink coffee in the morning.: Parts of the day take in. At night is the fixed exception.
Wrong: We arrived to London late. Right: We arrived in London late.: Arrive takes in for a city or country, and at for a building or event. It never takes to.
Wrong: I have lived here since three years. Right: I have lived here for three years.: For measures the length of time; since names the point where it started.
Wrong: The children are playing on the car. Right: The children are playing in the car.: A car is an enclosed space, so it takes in. On the car would mean on the roof or bonnet.

Questions learners ask

Why do we say "at night" but "in the morning"?

At night is an old fixed phrase, and English keeps it. The pattern for the other parts of the day is in the morning, in the afternoon and in the evening. Treat at night as one unit and use it at the end of a sentence: "The shop closes at night."

When do I use "at" and when do I use "to" with places?

At answers "where are you?" and to answers "where are you going?". "I am at the station" describes the location. "I am going to the station" describes the movement. The verb arrive is special: arrive at a place, arrive in a city or country, never arrive to.

What is the difference between "during" and "for"?

During tells you which period something happened in: "I fell asleep during the film." For tells you how long it lasted: "The film lasted for two hours." During takes a noun; for takes a length of time.