Prepositions are short words, but they cause many mistakes, because every language describes time and space in its own way. Turkish uses word endings instead of prepositions, and Spanish uses en in many places where English needs in, on or at.
The good news is that in, on and at follow a clear pattern, from big to small. For time, in is for long periods, on is for days and at is for exact times. For place, in is for an area or the inside of something, on is for a surface or a line, and at is for a point.
In, on and at: the basic rules
Think of the three words as a pyramid: in for the biggest periods and spaces, on in the middle, and at for the smallest, most exact points.
| Type | Pattern | Example |
|---|---|---|
| at (time) | clock times and exact moments | at 7 o'clock, at 6:45, at noon, at midnight, at sunset |
| on (time) | days and dates | on Monday, on Friday morning, on July 4, on my birthday |
| in (time) | months, years, seasons and longer periods | in June, in 2024, in (the) winter, in the 1990s, in the morning |
| at (place) | a point, an address or a place where an activity happens | at the door, at the bus stop, at 12 Oak Street, at work, at a party |
| on (place) | a surface, a line (a street, a river, a coast), a floor of a building, public transport | on the table, on the wall, on Oak Street, on the third floor, on the bus |
| in (place) | inside a space, or an area like a city or a country | in the box, in the kitchen, in a car, in Tokyo, in Mexico |
- Parts of the day: in the morning, in the afternoon, in the evening, but at night. With a specific day, use on: on Sunday morning, on Friday night.
- No preposition before next, last, this, every, today, tomorrow, yesterday and tonight: See you next Friday (not on next Friday). I'm busy this week.
- US and UK: Americans say on the weekend, while British speakers usually say at the weekend. For streets, Americans use on (on Main Street); British speakers use in or on (in Oxford Street).
- Dates: American English says on May 5 (May fifth); British English often writes on 5 May and says on the fifth of May.
When to use in, on and at
1. Time: at for clock times and exact moments
Use at for an exact point in time: a clock time, noon, midnight or sunrise. We also say at night and at the end of the day.
- The movie starts at 8:15.
- I usually go to bed at midnight.
- The city is very quiet at night.
2. Time: on for days and dates
Use on with days of the week, dates and special days. You can add a part of the day: on Monday morning, on Saturday night.
- I have a dentist appointment on Tuesday.
- She was born on March 12.
- We always have cake on my birthday.
3. Time: in for months, years, seasons and parts of the day
Use in for periods longer than a day, such as months, years, seasons, decades and centuries, and for the morning, the afternoon and the evening.
- My birthday is in July.
- They moved to Canada in 2019.
- I like to read in the evening.
4. Place: at for a point or a place with a purpose
Use at when you think of a place as a point on a map, or as the place where an activity happens, not as a space with an inside: at the door, at the station, at work, at school, at a party.
- Meet me at the bus stop.
- She's at work until six.
- We're at a party at Tom's house.
5. Place: on for surfaces, streets and public transport
Use on when something touches a surface (a table, a wall, the floor), for streets and the floors of a building, and for buses, trains and planes.
- Your keys are on the kitchen table.
- Our apartment is on the third floor.
- I always read on the train.
6. Place: in for the inside of a space or an area
Use in when something is inside a container, a room or a building, and for areas like neighborhoods, cities and countries. Use in for cars and taxis too.
- The milk is in the fridge.
- My cousin lives in Seoul.
- Get in the car, please.
Other prepositions of time: until, by and during
- before
- after
- from ... to
- until
- by
- during
- for
Until means up to that time (The store is open until 9 p.m.). By means not later than that time (Please send the form by Friday). During tells you when something happens inside a period (I fell asleep during the movie), while for gives the length of time (We stayed for two weeks).
Examples
Positive
- The meeting starts at 9:30.
- We play basketball on Saturdays.
- My grandparents live in a small village in Italy.
- There's a coffee shop at the end of the street.
Negative
- I don't work on Sundays.
- She isn't at home right now.
- We don't have classes in August.
- There isn't any milk in the fridge.
Questions
- Are you free on Friday evening?
- What do you usually do in the summer?
- Is your office on the fifth floor?
- Were you at the party last night?
In, on or at?
The same three words work for time and for place, and they follow the same idea: in for the biggest, on for the middle and at for the smallest, most exact point.
| Time | Place |
|---|---|
| at + an exact time: at 6:30, at noon, at midnight | at + a point or an address: at the door, at the bus stop, at 21 Elm Street |
| on + a day or a date: on Friday, on July 4, on Sunday morning | on + a surface or a line: on the table, on the wall, on Elm Street |
| in + a longer period: in May, in 2015, in the summer, in the morning | in + a space or an area: in the kitchen, in a box, in Chicago, in Brazil |
| no preposition: next week, last Friday, this morning, every day | no preposition with go home and come home (but: at home) |
Common mistakes
- WrongSee you in Monday.RightSee you on Monday.
Use on with days of the week and dates.
- WrongThe class starts in 9 o'clock.RightThe class starts at 9 o'clock.
Use at with clock times.
- WrongI was born at 1998.RightI was born in 1998.
Use in with years, months and seasons.
- WrongI'll call you on next week.RightI'll call you next week.
Do not use in, on or at before next, last, this or every.
- WrongShe is in home now.RightShe is at home now.
To say that someone is in their own house, English uses the fixed expression at home.
- WrongThere's a clock in the wall.RightThere's a clock on the wall.
Use on for things that hang on or touch a surface, like a wall.
Elena's working week
Examples of in, on and at are highlighted.
Elena works at a small hotel in Boston. Her day starts at 6:30 in the morning. She has breakfast in the kitchen and reads the news on the bus. The hotel is on Beacon Street, and her desk is on the first floor, next to the main entrance. She works from Monday to Friday, so she is free on weekends. In the summer, the hotel is very busy, and Elena often stays at work until nine. At night, she reads in bed or watches a movie on her laptop. Her birthday is on July 9, and this year she wants to spend it at the beach in Maine.
Prepositions of Time and Place quiz
8 questions. Choose an answer to see if it is right and why.
Read texts that use in, on and at
Grammar sticks when you meet it again in real reading. These graded texts use this structure; each one has key words, audio and questions.
Prepositions of Time and Place: questions and answers
What is the difference between in, on and at for time?
Use at for exact times (at 9:15, at noon), on for days and dates (on Tuesday, on May 1) and in for longer periods like months, years and seasons (in May, in 2020, in winter).
Is it on the weekend or at the weekend?
Both are correct. Americans say on the weekend (or on weekends), and British speakers usually say at the weekend.
Do we say in the bus or on the bus?
Say on the bus, on the train and on the plane, because these are large vehicles you can walk around in. For cars and taxis, use in: in the car, in a taxi.
Why do we say at night but in the morning?
There is no logical reason; these are simply fixed phrases in English. Learn them together: in the morning, in the afternoon, in the evening, but at night.
Can I say "See you Monday" without on?
Yes, in informal American English the on before days is often left out (See you Monday). If you are not sure, keep it: See you on Monday is correct everywhere.