Extended Time Prepositions

Use by for the latest acceptable time. The action may happen before that moment.

Use until when the action or state lasts up to that point and then stops.

Choose since with a starting point and for with a length of time.

Use from to introduce the beginning of a time range.

Pick the preposition from the meaning: inside an event, before a limit ends, or across the full period.

Deadlines

Use by when a task must be finished not later than a certain time. Anna will send the contract by noon.

Up to a point

Use until when an action or state lasts and then stops. Tom waited until 6 p.m.

Start vs length

Use since for the starting point and for for the length of time. Maria has lived here since 2020 and for four years.

Inside an event

Use during to place something inside a named event or period. Lisa checked her phone during the movie.

Whole period

Use throughout when something happens across the entire period. It stayed cold throughout the week.

No. By sets a deadline. Until shows that something continues and reaches that time point.

No. Since gives the starting point. For gives the length of time.

During places something at some time inside a period. Throughout means across the whole period.

Use by for a deadline or latest time

Use by when something happens before a time limit or not later than that point. The action can happen earlier, but the deadline is the end point.

Use until for something that continues up to a time point

Use until when a state or action lasts and stops at a specific time. Focus on duration up to the end point, not the deadline for one completed action.

Use since with the starting point

Use since before a point in time such as 2019, Monday, or 8 a.m. It shows when a situation started.

Use for with a length of time

Use for before a duration such as two hours, three weeks, or a long time. It answers how long, not from when.

Use from to mark the start of a time range

Use from to show where a time range begins, often with to or until: from 9 to 5, from Monday until Thursday.

Use during for something inside a period or event

Use during before nouns like the meeting, the night, or the summer. It places an action somewhere inside that period, not at the start point.

Use within for before a limit measured from now or from a starting moment

Use within when something must happen before a period ends, such as within two days or within an hour. The action happens sometime inside that limit.

Use throughout for all parts of a period

Use throughout when something continues or repeats during the whole period from beginning to end. It covers the entire time, not just one moment inside it.

Choose the preposition from the time expression

Look at the phrase after the preposition: a deadline, a start point, a duration, an event, or a full period. That cue tells you which preposition fits.