Prepositions of time
Prepositions of time are words such as "in", "on", "at", "since", "for", "during" and "by" that show when something happens or how long it lasts. They connect a noun or noun phrase referring to a time (a year, day, hour, season or period) to the rest of the sentence, showing its position or duration in time.
Types of prepositions of time
Point in time (at, on, in)
Used to say exactly when something happens, with the choice depending on whether it is a precise time, a day/date, or a longer period.
e.g. at 6 o'clock, on Monday, in July
Duration (for, during, since, from...to)
Used to show how long something lasts or the period across which it occurs.
e.g. for two hours, during the meeting, since 2010
Deadline or limit (by, until/till)
Used to mark the point before which something must happen or up to which a situation continues.
e.g. by Friday, until midnight, till next week
Sequence (before, after)
Used to show the order in which events happen relative to each other.
e.g. before dinner, after the exam
Approximate or additional time (around, in time, on time)
Used for rough timing or to describe punctuality.
e.g. around noon, in time for the show, on time for the meeting
Rules to remember
- Use "at" for precise clock times and certain fixed expressions (at 9 a.m., at night, at the weekend, at Christmas).
- Use "on" for days and dates (on Monday, on 5 May, on my birthday).
- Use "in" for longer periods such as months, years, seasons and parts of the day (in March, in 2024, in winter, in the morning).
- Use "for" with a length of time and "since" with a starting point (for three years, since 2020); do not confuse the two.
- Use "by" to mean "no later than" and "until" to mean "up to that point in time"; they are not interchangeable in most contexts.
Examples in sentences
| Example | How it works |
|---|---|
| The train departs at 7.45 in the morning. | "at" with a precise clock time; "in" with the part of the day. |
| We are meeting on Saturday to discuss the report. | "on" used with a specific day. |
| She has lived in this city since 2015. | "since" marks the starting point of a continuing situation. |
| I have been studying English for six years. | "for" shows the length of the period, not a specific point. |
| Please submit your application by Friday. | "by" indicates a deadline, meaning no later than that day. |
| There was a power cut during the storm. | "during" shows something happened within a specific event. |
| He always feels nervous before an interview. | "before" shows the sequence relative to another event. |
Common mistakes
Incorrect: I have lived here since five years.
Correct: I have lived here for five years.
Incorrect: She was born in Monday.
Correct: She was born on Monday.
Incorrect: We will finish the project until next week.
Correct: We will finish the project by next week.
Why this matters for IELTS
Accurate use of prepositions of time is a small detail that examiners notice quickly, and errors like "since three years" or "in Monday" can lower your Grammatical Range and Accuracy score even when your ideas are strong. In both Writing and Speaking, mixing simple time phrases (on Tuesday, in 2019) with more complex ones (by the time I graduated, during my previous job) shows range as well as accuracy, which examiners reward at Band 7 and above.
Frequently asked questions
What is the difference between "in", "on" and "at" for time?
"At" is for precise times (at 5 p.m.), "on" is for days and dates (on Monday, on 1 May), and "in" is for longer periods like months, years and seasons (in June, in 2023, in summer).
When do I use "for" instead of "since"?
Use "for" with a duration or length of time, such as "for two weeks", and use "since" with the specific point when something started, such as "since Monday" or "since 2018".
What is the difference between "by" and "until"?
"By" means an action must happen no later than a certain time (finish it by 6 p.m.), while "until" means a situation continues up to that time and then stops (I will wait until 6 p.m.).
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