Teaching English

English Grammar | Prepositions of time in, on, at, by and until

How to use the prepositions of time in, on, at, by and until. Example sentences included.

On this page you can find some guidelines on how to use the prepositions of time in, on, at, by and until, including example sentences to help you understand and express time-related concepts in English.

When to use "in"

We use “on” with months, years, seasons and time frames:

  • in April, May, etc.

We close in August for holidays.

  • in 1980, 2024, etc.

The company was founded in 1980.

  • in summer, spring, etc.

The company’s productivity remains high in winter.

  • in 2 minutes, 5 years, etc.

The meeting starts in 5 minutes.

When to use "on"

We use “on” with weekdays, dates and special days:

  • on Friday, Saturday, etc.

We don’t work on Saturday.

  • on 1st May, June 10th, etc.

We opened our first shop on October 20th.

  • on Christmas Day, etc.

What do you usually do on Christmas Day?

  • on the weekend (US)

We are always closed on the weekend.

When to use "at"

We use “at” with time, age, special periods and specific phrases:

  • at 10 o’clock, mealtime, etc.

We always close at 5pm.

  • at 23, the age of 40, etc.

I started working here at (the age of) 23.

  • at Christmas, Easter, etc.

Company sales peak at Christmas.

  • at the weekend (UK)

We are always closed at the weekend.

  • at the moment

I am busy at the moment.

Parts of the day

We say…

  • in the morning
  • in the afternoon
  • in the evening

We always have a briefing in the morning.


  • at night
  • at dawn

Security patrols the building at night.


  • on Friday morning
  • on Wednesday afternoon
  • on Friday night

We always have a meeting on Friday morning.

I usually go out on Saturday night.

In time or on time?

We say…

  • on time (not before/not after)

Our flight should arrive on time, unless there are unexpected delays.


  • in time for (not late)

Passengers should get to the airport in time for their flight.

Beginning/end & first/last:

We say…

  • at the beginning/end (where something starts/the last part of something)

At the beginning of the day I go to work, and at the end of the day I go home.


  • in the beginning/end (early stages/finally)

In the beginning my boss opposed the merger, but in the end he gave his consent.


  • at first/last (early stages/finally)

At first, I was afraid to take on new responsibilities, but at last I grew confidence.

We do not use in/on/at before...

… this

  • this morning;
  • this month, etc.

Are you going out for dinner this evening? 

… last

  • last June;
  • last Summer, etc.

I know what you did last summer.

… next

  • next Friday;
  • next week, etc.

I’ll be out of office next week.

… every

  • every day;
  • every summer, etc.

I work remotely every Friday.

By or until/till?

We say…

  • by + a time/date (= at that time or before)

I have to finish the report by y noon.


  • until/till + a time/date (= a specific endpoint in time)

I’ll be in a meeting untill/till 4pm. 

Downloadable educational resources

Printable worksheet for teachers and students available at up2dateskills online stores: up2 and TPT.

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