A2 Grammar Prepositions

Prepositions of Time: In, On, At and More

Prepositions of time tell us when something happens — in May, on Monday, at six o’clock, during the film, for two hours, since 2019. Knowing which one to use makes your English clear and natural.

Prepositions of time link an action to a moment or period of time. The three core prepositions — in, on and at — follow a fairly reliable pattern based on how long or how specific the time is. Around them sits a family of other prepositions such as during, for, since, by, until and from…to that mark duration, deadlines and limits.

This guide explains the main rules, the pairs that learners most often confuse (such as for and since, or by and until), and the fixed expressions worth memorising. Mastering these makes a big difference to fluency and accuracy.

In, On, At: The Big Three

The general rule moves from longer or less specific (in) to shorter and more precise (at).

Preposition Used for Examples
in months, years, seasons, parts of the day, long periods in May, in 2025, in summer, in the morning
on days and dates on Monday, on 5 June, on my birthday, on Friday morning
at clock times, festivals, points of time at 6 o’clock, at noon, at night, at Christmas, at the weekend

Watch out: We say in the morning / afternoon / evening, but at night. We say at the weekend in British English (Americans say on the weekend). When a day and a part of the day combine, use on: on Monday morning, on Friday evening.

For and Since: How Long

Both answer the question “how long?”, but they work differently. Use for with a period of time (how long it lasts) and since with a starting point (when it began).

for + period since + starting point
I’ve lived here for ten years. I’ve lived here since 2015.
We talked for an hour. We’ve been waiting since nine o’clock.
She studied for three months. He’s been ill since Monday.

Since is normally used with the present perfect or past perfect, because it links the past to a later time. See our guide to the present perfect.

During and For

Use during with a noun to say when something happens (within a period), and for with a length of time to say how long it lasts.

By and Until

These are easily confused. By means “not later than” a deadline (a single point), while until (or till) means “up to” a time (a continuous situation that then stops).

by (deadline) until / till (up to a point)
Finish the report by Friday. (at the latest on Friday) I’ll be at work until Friday. (continuously up to then)
Be home by ten. (no later than ten) We waited until ten. (and then stopped)

From…to / From…until

To mark the beginning and end of a period, use from…to or from…until.

No Preposition

Do not use a preposition before next, last, this, every, tomorrow, yesterday or today.

Common Mistakes

Practice Exercises

Grammar Quiz

Choose the right preposition of time for each situation.

Matching Pairs

Match time phrases to the preposition they take.

Cloze Dropdown

Select in, on, at or another time preposition to fill each gap.

Flash Cards

Drill prepositions of time and their fixed expressions.

Complete the Sentence

Type the correct preposition of time to finish each sentence.

Unjumble

Reorder scrambled words into natural sentences about time.

Practise Prepositions of Time

LexFizz has 30 free interactive exercises — no sign-up needed. Start mastering in, on and at today.

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Explore related grammar topics:

All Grammar Topics Prepositions Prepositions of Place Present Perfect Adverbs Tense Overview

Frequently Asked Questions

What are prepositions of time?
Prepositions of time are words that link an action to a moment or period of time, such as in, on, at, during, for, since, by and until. They answer the question “when?” or “how long?”: in May, on Monday, at six o’clock, for two hours, since 2019. Choosing the right one is essential for clear, natural English.
What is the difference between in, on and at for time?
Use in for longer or less specific periods — months, years, seasons and parts of the day (in May, in 2025, in the morning). Use on for days and dates (on Monday, on 5 June, on my birthday). Use at for clock times and precise points (at six o’clock, at noon, at night). The general pattern moves from the longest period (in) to the most precise point (at).
What is the difference between ‘for’ and ‘since’?
Use for with a length of time to say how long something lasts: I’ve lived here for ten years. Use since with a starting point to say when something began: I’ve lived here since 2015. Since is normally used with the present perfect or past perfect because it links a past starting point to a later time. A common error is to say “since ten years”; the correct form is “for ten years”.
What is the difference between ‘during’ and ‘for’?
Use during with a noun to say when something happens, within a period: I fell asleep during the film. Use for with a length of time to say how long something lasts: I slept for two hours. In short, during answers “when?” and is followed by a noun (during the holiday), while for answers “how long?” and is followed by a duration (for three days).
What is the difference between ‘by’ and ‘until’?
By means “not later than” a deadline, a single point: Finish the report by Friday (at the latest on Friday). Until (or till) means “up to” a time, describing a continuous situation that then stops: I’ll be at work until Friday (continuously up to then). Use by for deadlines and until for situations that continue up to a point and then end.
Do I say ‘at the weekend’ or ‘on the weekend’?
In British English we say at the weekend: What did you do at the weekend? In American English the usual form is on the weekend. Both are correct in their own variety. Similarly, British English says at Christmas and at Easter for the holiday periods, while a specific day takes on: on Christmas Day.
Why do we say ‘in the morning’ but ‘at night’?
This is an exception that simply has to be learned. We use in with the parts of the day — in the morning, in the afternoon, in the evening — but at with night: at night. When a part of the day is attached to a specific day, we switch to on: on Monday morning, on Friday night. These fixed combinations are worth memorising.
When do I use no preposition before a time expression?
Do not use a preposition before next, last, this, every, tomorrow, yesterday and today: See you next week (not “on next week”), We met last Friday, I’ll call you tomorrow, She swims every morning. Adding in, on or at before these words is a very common mistake.
How do I show the start and end of a period?
Use from…to or from…until to mark the beginning and end of a period: The shop is open from nine to five, I worked there from 2018 until 2022, We’re on holiday from Monday to Friday. The from marks the starting point and the to or until marks the end. Until emphasises that the situation continues right up to the end point.
At what level should I learn prepositions of time?
The core prepositions of time — in, on and at with days, months and clock times — are introduced at A1–A2, since they appear constantly in everyday English. The trickier pairs such as for versus since, during versus for, and by versus until are usually consolidated at B1, often alongside the present perfect, and remain useful to revise at higher levels.