Lesson

By and until, By the time...

Deadline expressions

≈ 15 min 8 block(s)

Text

By and until — What they mean

This lesson explains the difference between by, until, and the phrase by the time. These expressions talk about time, but they are used in different ways:

"by" indicates a deadline or a point no later than which something happens or is completed.
"until" (or "till") indicates continuation up to a specific time — the action continues and stops at that point.
"by the time" connects two events and shows that one event is completed before or when the other starts.

Table

By vs Until vs By the time

Structure	Meaning	Example
by + time (deadline)	No later than that time; completion before or at that point	Please send the report by Friday.
until / till + time	Action continues up to that time and stops then	She will be in the office until 6 PM.
by the time + clause	Shows that one event is completed before or when another happens	By the time the meeting started, I had already emailed the file.
by + present/perfect (with future meaning)	Commonly used with future perfect to show completion before a future time	I will have finished the draft by Monday.

Tip

Key rule: deadline vs duration vs sequence

Remember the core differences:

"By" = deadline (when something must be completed) — think 'no later than'.
"Until" = duration (up to a point) — action continues and stops at that time.
"By the time" links events: use it to say that one event is already finished when another happens.

For deadlines, use 'by' with simple times or the future perfect (I will have finished by Wednesday). For duration, use 'until' with the verb tense appropriate to the time frame.

Example

Examples in context

Please submit the proposal by Monday.

The office is open until 7 PM.

By the time you arrive, we will have completed the presentation.

She worked on the project until she received approval.

Tip

Common mistakes to avoid

Watch out for these universal errors:

Using 'by' when you mean 'until' (e.g., saying 'I will work by 6 PM' to mean continuous work until 6).
Using 'until' to indicate a deadline rather than duration.
Wrong tense after 'by the time' — it often requires a perfect tense to show completion (past perfect or future perfect).
Confusing the sequence of events: not realizing 'by the time' implies completion before or at the moment of the other event.
Dropping 'the' in 'by the time' in contexts where the phrase requires it.

Focus on meaning first (deadline vs duration vs sequence); then choose the correct preposition and tense.

Quiz

Choose the correct sentence that shows a deadline:

Hint: Look for the expression that means 'no later than' a specific day.

Quiz

Complete: I _____ the first draft by Friday.

Hint: Think about the verb form that shows completion before a future time.

Quiz

Which sentence means the action stopped at a specific time?

Hint: Look for the option that indicates continuation up to a point in time.

Key Points

GrammarPoint

by

preposition CEFR B1 //baɪ//

Indicates a deadline or a point in time no later than a stated moment.

Submit the invoice by Friday.

GrammarPoint

until

preposition/conjunction CEFR B1 //ənˈtɪl/ or /tɪl//

Indicates that an action continues up to a particular time and stops then.

The team worked until midnight to meet the deadline.

GrammarPoint

by the time

expression CEFR B2 //baɪ ðə taɪm//

Links two events and shows that one event was already completed when the other occurred.

By the time the CEO arrived, the presentation had finished.

Vocabulary

deadline

noun CEFR B1 //ˈdɛdˌlaɪn//

A date or time by which something must be done.

We have a tight deadline for the quarterly report.

GrammarPoint

future perfect

grammar term CEFR B2 //ˈfjuːtʃər ˈpɜːrfɪkt//

A verb tense (will have + past participle) used to show that an action will be completed before a specific future time.

I will have sent the documents by Tuesday.

Vocabulary

duration

noun CEFR B1 //djʊˈreɪʃən//

The length of time something lasts.

The duration of the training is three days.