Understanding the difference between for and since is important for speaking and writing English correctly. Both words help us talk about time, but they have different meanings and uses.
We use for to describe how long an action or situation lasts. We use since to explain when an action or situation started.
For example:
- I have studied English for three years.
- I have studied English since 2023.
Both sentences describe an activity that started in the past and continues into the present. However, for focuses on the length of time, while since identifies the starting point.
In this guide, you will learn how to use for and since in English, understand their grammar rules, and explore practical examples. You will also discover common mistakes, sentence structures, and exercises to help you use these time expressions confidently.
Table of Contents
What Is the Difference Between For and Since?
The main difference between for and since is that for expresses a duration of time, while since identifies a specific starting point.
For answers the question “How long?”
Since answers the question “Since when?”
Consider these examples:
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She has worked here for five years.
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She has worked here since 2021.
In the first sentence, for five years tells us how long she has worked at the company. In the second sentence, since 2021 tells us when she started working there.
Both expressions can describe situations that began in the past and continue into the present.
For vs Since: Comparison Table
The following table explains the key differences between for and since in English grammar.
| Grammar Feature | For | Since |
|---|---|---|
| Meaning | Expresses a duration of time | Identifies a starting point |
| Main question | How long? | Since when? |
| Time reference | A period of time | A specific point in time |
| Common expressions | For two hours, for five days | Since Monday, since 2020 |
| Present perfect | I have lived here for ten years. | I have lived here since 2016. |
| Present perfect continuous | She has been studying for three hours. | She has been studying since noon. |
| Other tenses | Can describe duration in past, present, or future contexts | Commonly used with perfect tenses when describing continuing situations |
| Main purpose | Shows how long something lasts | Shows when something began |
Basic Grammar Rules for For and Since
To understand the difference between for and since, remember these two basic grammar rules.
Rule 1: Use For + Period of Time
Use for when you want to describe the length of time an action or situation lasts.
Structure:
Subject + verb + for + period of time
Examples:
-
I have lived here for six years.
-
She studied for two hours.
-
We have been friends for a long time.
-
They stayed at the hotel for three nights.
In these examples, for tells us the duration of each action or situation.
Rule 2: Use Since + Starting Point
Use since when you want to identify when an action or situation began.
Structure:
Subject + have/has + past participle + since + starting point
Examples:
-
I have lived here since 2020.
-
She has worked at this school since January.
-
We have known each other since childhood.
-
He has been busy since Monday.
In these examples, since identifies the starting point of an action or situation that continues into the present.
Important: When since introduces a starting point for a continuing situation, we commonly use it with the present perfect or present perfect continuous tense. However, since also has other grammatical uses, which we will explore later.
For vs Since: Examples in Sentences
Compare the following sentences to understand how for and since express time differently.
| Using For | Using Since |
|---|---|
| I have worked here for five years. | I have worked here since 2021. |
| She has studied English for three years. | She has studied English since 2023. |
| They have lived together for ten years. | They have lived together since 2016. |
| He has been waiting for two hours. | He has been waiting since 8 a.m. |
| We have been friends for many years. | We have been friends since childhood. |
These examples show that for describes how much time has passed, while since identifies when the period began.
The two expressions are not interchangeable because they refer to different aspects of time.
Quick Tip: Remember this simple rule:
-
For = Duration: How long?
-
Since = Starting point: Since when?
Understanding this difference will help you choose the correct expression in everyday English conversations and writing.
How to Use For in English
We use for to describe the duration of an action, event, or situation. It tells us how long something happens, happened, or will happen.
When talking about time, for is followed by a period of time, such as two hours, three days, six months, or several years.
Examples:
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I have lived in this city for five years.
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She studied English for two hours.
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We stayed at the hotel for three nights.
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He will travel abroad for two weeks.
In these sentences, for explains the length of time associated with each action.
Grammar Rules for Using For
There are several important grammar rules to remember when using for to express time.
Rule 1: Use For Before a Period of Time
We use for before expressions that describe how long something lasts.
Structure:
Subject + verb + for + period of time
Examples:
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I waited for thirty minutes.
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She has worked here for six years.
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They played football for an hour.
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We have known each other for a long time.
Rule 2: Use For with Different Verb Tenses
We can use for with different English verb tenses to describe durations in the past, present, or future.
Examples:
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Present perfect: I have studied English for four years.
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Present perfect continuous: She has been reading for two hours.
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Past simple: We lived in London for three years.
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Past continuous: They were waiting for an hour before the bus arrived.
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Future simple: I will stay here for two weeks.
The verb tense tells us when an action occurs, while for expresses its duration.
Rule 3: Use For with Both Completed and Continuing Actions
We can use for to describe actions that have already finished or situations that are still continuing.
Examples:
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I worked at that company for five years. (Completed action)
-
I have worked at this company for five years. (Continuing situation)
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She slept for eight hours. (Completed action)
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She has been sleeping for two hours. (Continuing action)
The meaning depends on the verb tense and context.
Sentence Structures with For
Understanding sentence structures will help you use for correctly in affirmative, negative, and interrogative sentences.
| Sentence Type | Structure | Example |
|---|---|---|
| Affirmative | Subject + verb + for + duration | I have lived here for ten years. |
| Negative | Subject + negative verb + for + duration | I haven’t seen him for two weeks. |
| Question | Auxiliary + subject + verb + for + duration? | Have you worked here for five years? |
| Past simple | Subject + past verb + for + duration | She stayed there for a month. |
| Future simple | Subject + will + base verb + for + duration | We will travel for two weeks. |
Affirmative Sentences
Use for to explain how long an action or situation lasts.
Examples:
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I have been learning English for six months.
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She has lived in Canada for several years.
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We talked for an hour.
Negative Sentences
We can use for in negative sentences to describe how long a situation has continued.
Examples:
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I haven’t visited my hometown for three years.
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She hasn’t spoken to him for two weeks.
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We haven’t watched a movie for a long time.
Interrogative Sentences
Use for in questions when asking about a particular duration.
Examples:
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Have you lived here for ten years?
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Did she study for three hours?
-
Will you stay for another week?
We can also use how long to ask about duration.
Examples:
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How long have you lived here?
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How long did you wait?
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How long will you stay?
The answers may include for:
-
For five years.
-
For thirty minutes.
-
For two weeks.
Common Time Expressions with For
The word for can be used with many expressions of duration.
| Time Expression | Example Sentence |
|---|---|
| For a few seconds | The lights went out for a few seconds. |
| For ten minutes | I waited for ten minutes. |
| For two hours | She has been studying for two hours. |
| For three days | We stayed there for three days. |
| For a week | He was sick for a week. |
| For several months | They have been preparing for several months. |
| For five years | I have worked here for five years. |
| For a long time | We have been friends for a long time. |
| For ages | I haven’t seen you for ages. |
| For a while | Let’s rest for a while. |
These expressions are common in everyday English conversations.
Examples of For in Everyday English Sentences
Here are additional examples showing how to use for naturally in different situations.
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I have been waiting for the bus for twenty minutes.
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She has studied English for three years.
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We lived in New York for six months.
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He worked on the project for several weeks.
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They have been married for ten years.
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I haven’t visited my grandparents for a long time.
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The children played outside for two hours.
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She will stay with her relatives for a week.
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We have been learning grammar for several months.
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He has been working from home for two years.
When Can We Omit For?
In some English sentences, we can omit for before a duration, especially when using expressions such as all day, all night, all week, or all morning.
Examples:
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I worked all day. (Natural)
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She studied all night. (Natural)
-
We waited all morning. (Natural)
We can also omit for before certain duration expressions in informal English.
Examples:
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I stayed there three days.
-
I stayed there for three days.
Both sentences are grammatically correct. However, including for often makes the duration clearer, especially for beginner English learners.
Remember: Use for when you want to explain how long an action, event, or situation lasts. It can describe both completed and continuing actions and can be used with several different verb tenses.
How to Use Since in English
We use since to identify the starting point of an action or situation. It tells us when something began, especially when the action or situation continues into the present.
The word since is commonly followed by a specific time, date, year, day, or event.
Examples:
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I have lived in this city since 2020.
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She has worked at this company since January.
-
We have known each other since childhood.
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He has been studying since 8 a.m.
In these sentences, since identifies when each action or situation began.
Grammar Rules for Using Since
There are several important grammar rules to remember when using since in English.
Rule 1: Use Since Before a Specific Starting Point
We use since before a particular time or event that marks the beginning of an action or situation.
Structure:
Subject + have/has + past participle + since + starting point
Examples:
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I have lived here since 2018.
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She has worked at the hospital since March.
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They have been friends since high school.
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We have owned this house since 2021.
The expressions 2018, March, high school, and 2021 identify starting points.
Rule 2: Use Since with Continuing Actions or Situations
When describing an action or situation that began in the past and continues into the present, we commonly use since with the present perfect or present perfect continuous tense.
Examples:
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I have known him since childhood.
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She has been learning English since January.
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They have lived in Canada since 2019.
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He has been working on this project since Monday.
These sentences describe actions or situations that started in the past and are still continuing.
Rule 3: Use Since with a Time Expression or Clause
The word since can be followed by a time expression or a clause that identifies when something began.
Examples:
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She has been here since morning.
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I have known her since we were children.
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He has worked remotely since he moved to London.
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We haven’t met since the conference ended.
A time expression identifies a particular starting point, while a clause describes an event that marks the beginning of a period.
Sentence Structures with Since
Understanding sentence structures will help you use since correctly in affirmative, negative, and interrogative sentences.
| Sentence Type | Structure | Example |
|---|---|---|
| Affirmative | Subject + have/has + past participle + since + starting point | I have lived here since 2020. |
| Negative | Subject + haven’t/hasn’t + past participle + since + starting point | She hasn’t visited us since June. |
| Question | Have/Has + subject + past participle + since + starting point? | Have you worked here since 2021? |
| Present perfect continuous | Subject + have/has + been + verb-ing + since + starting point | He has been studying since 9 a.m. |
| Since + clause | Subject + have/has + past participle + since + subject + past simple verb | We have been friends since we met at school. |
Affirmative Sentences with Since
We use since in affirmative sentences to describe when an ongoing action or situation began.
Examples:
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I have lived in this neighborhood since 2019.
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She has been teaching English since September.
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They have known each other since childhood.
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We have been waiting since noon.
Negative Sentences with Since
We use since in negative sentences to explain that an action has not happened from a particular point in the past until now.
Structure:
Subject + have/has + not + past participle + since + starting point
Examples:
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I haven’t seen my cousin since Christmas.
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She hasn’t called me since Monday.
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We haven’t visited that restaurant since last summer.
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He hasn’t played football since his injury.
In these examples, the action last happened at or around the specified starting point and has not happened again up to the present.
Interrogative Sentences with Since
We use since in questions to ask whether an action or situation has continued from a particular starting point.
Structure:
Have/Has + subject + past participle + since + starting point?
Examples:
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Have you lived here since 2020?
-
Has she worked at this school since January?
-
Have they been friends since childhood?
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Has he been studying since this morning?
We can also use since when to ask about the starting point of an action or situation.
Examples:
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Since when have you lived here?
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Since when has she worked at this company?
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Since when have they known each other?
Note: Since when is grammatically correct, but it can sometimes express surprise or disbelief, depending on the speaker’s tone. In neutral conversation, questions such as When did you start working here? may sound more natural.
Common Time Expressions with Since
The word since can be followed by different expressions that identify a starting point.
| Time Expression | Example Sentence |
|---|---|
| Since Monday | I haven’t seen her since Monday. |
| Since yesterday | He has been feeling better since yesterday. |
| Since this morning | She has been working since this morning. |
| Since 8 a.m. | We have been waiting since 8 a.m. |
| Since January | I have worked here since January. |
| Since 2020 | They have lived in London since 2020. |
| Since last week | She has been busy since last week. |
| Since childhood | We have been friends since childhood. |
| Since graduation | He has worked abroad since graduation. |
| Since then | I haven’t spoken to him since then. |
These expressions are commonly used in everyday English when describing situations that began in the past.
How to Use Since with a Clause
The word since can introduce a clause that describes an event or situation marking the beginning of a period.
A clause contains a subject and a verb.
Structure:
Main clause + since + subject + verb
When describing an ongoing situation that began after a completed past event, we commonly use the present perfect in the main clause and the past simple in the since clause.
Examples:
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I have lived here since I graduated from university.
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She has worked remotely since she moved to Canada.
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We have been friends since we met at school.
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He has been happier since he changed jobs.
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They have visited us regularly since they bought their house.
In each example, the since clause identifies the event that marks the starting point.
Important Grammar Note:
The verb after since does not always have to be in the past simple. Other verb forms are possible depending on the intended meaning.
For example:
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I have felt much better since I started exercising.
-
I have learned a lot since I have been working here.
Both sentences are grammatically correct, but they express slightly different relationships between the events.
How to Use Since Then
The expression since then means from that time until now, or until another reference point established by the context.
We use it when the starting point has already been mentioned.
Examples:
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I moved to Chicago in 2020. I have lived here since then.
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She started her business last year. She has been very busy since then.
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We met at university. We have remained friends since then.
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He changed his job in January. He has been happier since then.
The expression since then helps avoid repeating a date or event.
Examples of Since in Everyday English Sentences
Here are ten additional examples showing how to use since naturally in different situations.
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I have been learning English since 2022.
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She has lived in this apartment since last summer.
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We have known each other since elementary school.
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He has been working on his assignment since breakfast.
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They have been married since 2015.
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I haven’t received any messages since yesterday.
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She has been interested in music since childhood.
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We have been waiting for the teacher since 9 a.m.
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He has worked at the university since he graduated.
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I have enjoyed reading books since I was a child.
Since as a Preposition, Conjunction, and Adverb
In English grammar, since can function as a preposition, conjunction, or adverb.
| Grammatical Function | Explanation | Example |
|---|---|---|
| Preposition | Followed by a noun or time expression | I have lived here since 2020. |
| Conjunction | Introduces a clause | I have known her since we were children. |
| Adverb | Refers to a previously mentioned time | He left in June, and I haven’t seen him since. |
Since as a Preposition
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She has worked here since March.
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I haven’t eaten anything since breakfast.
Since as a Conjunction
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We have been close friends since we met.
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He has felt better since he started exercising.
Since as an Adverb
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She moved away in 2021, and I haven’t seen her since.
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He graduated last year and has since found a job.
Remember: When talking about time, since identifies when an action or situation began. It is especially common with the present perfect and present perfect continuous tenses, and it can introduce both time expressions and clauses.
For vs Since: Key Differences
The main difference between for and since is how they describe time. We use for to express the duration of an action or situation, while since identifies the point when it began.
Although both expressions are commonly used with the present perfect tense, they answer different questions.
-
For: How long has something continued?
-
Since: When did something begin?
Understanding this distinction will help you choose the correct time expression in English sentences.
For vs Since: Comparison Table
The following table summarizes the key differences between for and since.
| Feature | For | Since |
|---|---|---|
| Meaning | Duration of time | Starting point in time |
| Answers | How long? | Since when? |
| Time reference | A length of time | A specific time or event |
| Common expressions | Two hours, three days, five years | Monday, January, 2020 |
| Example | I have worked here for five years. | I have worked here since 2021. |
| Completed actions | Can describe completed durations | Usually marks a starting point rather than a completed duration |
| Continuing situations | Commonly used | Commonly used |
| Main focus | How much time has passed | When the period began |
For vs Since: Examples in Sentences
Compare these sentence pairs to understand how the two expressions describe the same situation from different perspectives.
| Using For | Using Since |
|---|---|
| I have lived here for six years. | I have lived here since 2020. |
| She has worked here for three years. | She has worked here since 2023. |
| We have been friends for ten years. | We have been friends since 2016. |
| He has been studying for two hours. | He has been studying since 8 a.m. |
| They have been married for five years. | They have been married since 2021. |
| I haven’t seen her for two weeks. | I haven’t seen her since last Monday. |
Note: The dates and durations are illustrative. Whether they describe the same exact period depends on when the sentences are spoken.
In each pair, for emphasizes the length of time, while since emphasizes the starting point.
How to Choose Between For and Since
You can choose the correct expression by asking yourself one simple question:
Am I describing a duration or a starting point?
Follow this decision guide:
Step 1: Identify the Time Expression
Look at the words that follow for or since.
Examples:
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Three hours
-
Last Monday
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Five years
-
January
-
A long time
-
When I was a child
Step 2: Decide What the Expression Describes
If the expression describes a length of time, use for.
Examples:
-
For three hours
-
For five years
-
For a long time
If the expression identifies when something began, use since.
Examples:
-
Since last Monday
-
Since January
-
Since I was a child
Step 3: Complete the Sentence
Choose the expression that matches the intended meaning.
Examples:
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I have been studying English for three years.
-
She has been working here since January.
-
We have been waiting for thirty minutes.
-
He has lived in this city since childhood.
Quick For vs Since Reference Chart
| Use For With | Use Since With |
|---|---|
| A number of minutes | A specific clock time |
| A number of hours | A particular day |
| A number of days | A particular date |
| A number of weeks | A particular month |
| A number of months | A particular year |
| A number of years | A specific past event |
| A long time | Childhood or graduation |
Can For and Since Be Used Interchangeably?
No. For and since are not interchangeable when expressing duration and starting points.
Compare:
-
Correct: I have lived here for five years.
-
Incorrect: I have lived here since five years.
And:
-
Correct: She has worked here since 2021.
-
Incorrect: She has worked here for 2021.
The incorrect sentences confuse a duration with a starting point.
Quick Tip: If you can answer the question How long?, use for. If you can answer Since when?, use since.
Once you understand this distinction, choosing between for and since becomes much easier in everyday English conversations and writing.
Conclusion
Understanding the correct use of “for and since” is essential for grammatically correct speaking and writing in English. As mentioned, the word “for” focuses on the length of time, whereas the word “since” tells us when something began, that is starting point in time. By practicing and using these two small words in your daily English speaking and writing practice, you will be able to use them correctly and efficiently.
I hope this article helped you learn the difference between for and since and their correct usage in English sentences. By using these two words in your daily speaking and writing practice, you will be better at using them correctly.