The Difference between the Words ‘When’ and ‘While’

When and while are two words that are often confused by intermediate English language learners. As is often the case with confusing words, these particular two words can sometimes be interchanged but frequently have distinct meanings of their own.

When and while can fall into a number of word classes, but it is when they are used as subordinating conjunctions that confusion frequently arises. This is typically because both words can introduce subordinate clauses that relate to time. However, they convey specific meanings.

For more on conjunctions, please visit this post.


‘When’ as a subordinating conjunction

When introduces a clause that specifies the time at which something happens. It often marks a specific point in time or an event that triggers another event.


Specific point in time:

  • When he arrived, the meeting had already started.”
    • This sentence specifies the exact moment (his arrival) at which the meeting’s status is noted (already started).

Cause and effect:

  • “She felt happy when she heard the news.”
    • Here, when introduces the event (hearing the news) that causes the main action (feeling happy).

Repeated actions:

  • When I visit my grandparents, we always bake biscuits.”
    • This sentence describes a recurring event (visiting grandparents) and its associated action (baking biscuits).

‘While’ as a subordinating conjunction

While introduces a clause that specifies an event happening simultaneously with another event. It emphasises the duration or the overlapping nature of two actions.


Simultaneous actions:

  • “She sang while he played the piano.”
    • This sentence indicates that both actions (singing and playing the piano) occur at the same time.


  • While I prefer tea, he likes coffee.”
    • Here, while is used to show contrast between two preferences.


  • “We talked about our plans while we walked to the park.”
    • This example emphasises the duration of the conversation (the entire time they walked to the park).

when and while

Clarifying the differences with further examples

Correct usage of ‘when’:

  • When the clock struck midnight, the fireworks began.”
    • When correctly introduces a specific moment in time.

Correct usage of ‘while’:

  • While the clock was striking midnight, the fireworks began.”
    • While correctly indicates that the clock striking midnight and the beginning of the fireworks occurred simultaneously.

Etymological Origins


The word when originates from Old English “hwænne”, which evolved from Proto-Germanic “*hwan”, and ultimately from Proto-Indo-European “*kʷis”, a base meaning who or what. It is related to the Old High German “wenne” and the Old Norse “hvenær”.

When has been used in English since before the 12th century, primarily as a word to ask questions about time or to introduce clauses about time.


While comes from the Old English “hwīl”, which means “a space of time” or “a while”. It shares roots with Old Saxon “hwīl” and Old High German “hwīla”, both meaning “a time” or “period”.

The use of while in English also dates back to before the 12th century. Initially, it was more focused on denoting a period rather than simultaneous events.


Why they are confused

When and while are often confused because they both relate to the concept of time. Both when and while connect events in time, making it easy to mix them up. The context often determines the choice between when and while, so without clear temporal markers, it can be challenging to decide which word to use. For non-native English speakers, the subtle differences in use can be particularly confusing because similar subordinating conjunctions in their native languages might not have the same distinctions.

Types of words

The difference between when and while becomes clearer when one looks at what parts of speech they can function as:

When is primarily a conjunction, an adverb and a pronoun.

While is primarily a conjunction and a noun.

Usage and examples


1. As a conjunction

Used to introduce the time at which an event occurs.

  • I was reading a book when the phone rang.
  • When the sun sets, the sky turns orange.
  • Call me when you get home.

2. As an adverb

To describe time in relation to a verb. While, when is also a common question word (who, what, why, where, when), while is not.

  • When are you leaving?
  • He didn’t know when she would arrive.
  • When will you arrive?

3. As a pronoun

The time at which.

  • I remember the days when we used to play outside.
  • Do you recall when we last met?
  • I remember when we first met.


1. As a conjunction

Used to indicate that two events are happening simultaneously.

  • I listened to music while doing my homework.
  • She was cooking dinner while talking on the phone.
  • She read a book while waiting for the bus.

2. As a noun

A period of time.

  • We talked for a while.
  • After a while, he decided to leave.
  • It took a while to finish.


Similar words and confusions

The following words can also be subordinating conjunctions and also refer to time:

As is similar in function to while when indicating simultaneous events.

  • As she sang, he played the guitar.

During is used to denote a period within which something happens, similar to while.

  • She stayed quiet during the meeting.

Since indicates a point in time from the past until now, which can sometimes be confused with when.

  • I have been studying since this morning.

Until marks the end point of a period, often confused with while or when.

  • Wait here until I come back.


Understanding the subtle differences between when and while, and other subordinating conjunctions conveying time, helps in using them correctly. When focuses on the specific point in time at which an event occurs, while while emphasises the duration or the simultaneous occurrence of two events. The distinct origins of these two words in the English language explains their individual uses and how they have grown closer together over the years to become a foundation of the modern English language.

In summary, to avoid confusion between when and while as subordinating conjunctions, one must focus on their specific functions:

  • Use when to introduce a specific point in time or to indicate a cause-and-effect relationship.
  • Use while to emphasise simultaneous actions, contrast, or duration.

With understanding and practice, correct usage will become more intuitive.

If you have any further questions, please do enter them below.


Börjars, Kersti, and others. Introducing English Grammar, 2nd edn (Routledge, 2010)

Burton-Roberts, Noel. Analysing Sentences: An Introduction to English Syntax, 4th edn (Routledge, 2016)

Cresswell, Julia. Oxford Dictionary of Word Origins, 3rd edn (Oxford University Press, 2021)

Crystal, David. The Cambridge Encyclopedia of the English Language, 3rd edn (Cambridge University Press, 2019)

Hewings, Martin, and others. Cambridge English Grammar and Vocabulary for Advanced (Cambridge University Press, 2015)

Huddleston, Rodney, and others. The Cambridge Grammar of the English Language (Cambridge University Press, 2002)

Parrott, Martin. Grammar for English Language Teachers, 2nd edn (Cambridge University Press, 2011)

Quirk, Randolph, and others. A Comprehensive Grammar of the English Language, reprint edn (Pearson, 2011)

New Hart’s Rules: The Handbook of Style for Writers and Editors (Oxford University Press, 2005)

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