The Difference between For and Since

Understanding when to use “for” and “since” can be tricky for many English learners, but mastering them makes your sentences clear and accurate. Both words are used to talk about time, but they have different purposes. “For” refers to a duration of time, while “since” points to a specific starting point. In this blog, we’ll break down the difference with easy explanations and examples, so you can use them confidently in everyday conversations and writing.

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Introduction

Many English learners often get puzzled by the words “for” and “since” because both relate to time, but they are used differently. Understanding the difference between them can make your sentences more precise and natural.

• “For” is used to describe a length or duration of time—how long something has been happening. For example, “I have been studying English for three years” tells us the total time spent studying.
• “Since”, on the other hand, points to a specific starting point in time—the exact moment when something began. For example, “I have been studying English since 2020” shows the starting year of the action.

Many beginners mix them up because both talk about time, but remembering that “for” = duration and “since” = starting point makes it easier to use them correctly. Using these words accurately helps conversations and writing sound more fluent and clear.

Understanding Duration vs. Starting Point

When talking about time in English, it’s important to understand the difference between duration and starting point, because these two ideas help us choose the right word—for or since. Many learners mix them up, but once you understand the concept clearly, using them becomes very easy.

What is Duration?

Duration refers to how long something has been happening. It focuses on the length of time — the total period from the beginning until now. Duration does not tell us exactly when something started. It simply shows the amount of time that has passed.

For example:

• “I have been studying English for three years.” Here, the important information is the length of time — three years — not the year or date you started.

Duration answers the question: “How long has this been happening?”

Think of duration as the length of the movie, not when the movie started. Words like for are used to express duration.

What is a Starting Point?

On the other hand, a starting point tells us when something began. It marks the exact moment an action or situation started and continues until now. Instead of telling us the length of time, it points to the beginning.

For example:

• “I have been studying English since 2020.” This sentence gives the specific year when the studying began.

Starting point answers the question: “When did this begin?”

Think of a starting point as the time the movie began, not how long it has been playing. Words like since are used to express the starting point.

Why Understanding the Difference Matters

Many English learners mix up “for” and “since”, even though they express different ideas. Using the wrong one can make your sentence confusing or incorrect.

Remember:

• For = Duration (How long)

• Since = Starting point (When it began)

Correct usage examples:

• “She has lived here for six years.” → duration

• “She has lived here since 2018.” → starting point

Understanding this difference helps you express time clearly, whether you’re talking about habits, experiences, or ongoing situations. It also makes your English sound more natural and confident.

Both duration and starting point help us express ongoing actions clearly. Once you connect for = how long and since = when it started, your sentences become more natural and accurate. This small understanding makes a big difference in sounding fluent and confident in English.

How to Use “For” Correctly (Rules + Examples)

“For” is used to talk about duration — the length of time something lasts. Below are clear rules, easy examples, and helpful tips written in simple, human-friendly sentences.

1. Use “for” with a period of time

Use for when you want to say how long something happened or has been happening.

Examples:

• I studied for two hours.

• They lived in Mumbai for five years.

• She practised the piano for thirty minutes every day.

2. Common time words used with “for”

“For” pairs naturally with words that show length or amount, such as: minutes, hours, days, weeks, months, years, a long time, a short time, ages.

Examples:

• for ten minutes

• for three weeks

• for a long time

• for ages

3. Use “for” with perfect tenses to show ongoing duration

When you talk about actions that started in the past and continue now, use for with present perfect or present perfect continuous.

Examples:

• I have worked here for six years.

• She has been learning French for three months.

• We’ve been waiting for half an hour.

4. Use “for” with past simple to show completed durations

If the action is finished, use for with past simple to show how long it lasted.

Examples:

• He slept for eight hours last night.

• They stayed in Rome for two weeks last summer.

5. Use “for” in requests and offers

“For” can appear when explaining the purpose or reason in casual speech (though “for” here is not about time, it’s common). Keep this in mind so you don’t confuse the uses.

Examples:

• This gift is for you. (purpose)

• Can you book a taxi for 7 PM? (time reference to an appointment — still okay)

6. Avoid common mistakes

1. Wrong: I have lived here for 2018.

    Right: I have lived here since 2018. (use since for a specific start point)

2. Wrong: She worked here since two years.

    Right: She worked here for two years. (use for with lengths, since with start points)

7. Quick memory trick

Ask “How long?” — if the answer is a length of time (two hours, five years), use for.

8. Short practice set (try to fill in the blank)

1. I’ve known him ___ ten years. → for

2. They waited ___ three hours. → for

3. She studied Spanish ___ a year before moving. → for

How to Use “Since” Correctly (Rules + Examples)

“Since” is used to talk about the starting point of an action or situation — the exact time something began and continues until now. It helps us show when something started.

Below are clear rules and easy examples to help you use since correctly and confidently.

1. Use “since” with a specific starting time

“Since” always shows the exact beginning of an action. This can be a year, date, month, day, time, age, event, or moment.

Examples:

• I have lived here since 2015.

• She has worked at the hospital since January.

• They have been friends since childhood.

• He has been awake since 6 AM.

All of these show the starting point clearly.

2. Use “since” with perfect tenses

“Since” is normally used with the present perfect or present perfect continuous because these tenses describe actions that began in the past and continue into the present.

Examples:

• I have been learning English since 2020.

• She has been reading that book since morning.

• We have known each other since school.

These sentences show an ongoing action from a specific point until now.

3. “Since” can refer to a specific event

The starting point does not always have to be a date or time. It can also be an event.

Examples:

• She has been happier since her vacation.

• He hasn’t eaten junk food since his last health check-up.

• Life has changed a lot since the pandemic.

Here, the event marks the moment the change began.

4. Use “since” to express a reason (separate meaning)

Sometimes “since” means because, but this is a different use. Be careful not to confuse it with the time expression.

Examples:

• Since it was raining, we stayed home.

• Since you’re here early, we can start now.

If the sentence makes sense when replaced with “because,” it’s the reason-giving meaning.

5. Avoid common mistakes

• Wrong: I have lived here since 10 years.
  ✔ Correct: I have lived here for 10 years.
  (Use since with a starting point, not a duration.)

• Wrong: She worked here since 2018.
  ✔ Correct: She has worked here since 2018.
  (Use perfect tenses with since.)

6. Quick Memory Trick

Think of “since” = “from when”.

If your answer includes a point in time, use since.

Examples:

• When did it start? 2010 → since 2010

• When did she move? Last week → since last week

Common Errors Learners Make with For and Since

Here are the most frequent mistakes learners make when using for and since, with clear explanations, corrected examples, and simple tips to remember what’s right.

1. Using since with a duration instead of a starting point

Wrong: I have lived here since five years.

Right: I have lived here for five years.

Why: Since needs a specific starting point (a year, date, time, or event). Use for when you say how long (a duration).

Tip: Ask “How long?” — if the answer is “five years,” use for.

2. Using for with a starting point

Wrong: I have worked here for 2018.

Right: I have worked here since 2018.

Why: Years and specific dates are starting points, so since is required.

Tip: Replace since with “from” in your mind: “from 2018” → since 2018.

3. Forgetting to use the perfect tense with since

Wrong: She since 2019 at the company. / She worked here since 2019.

Right: She has worked here since 2019.

Why: Since normally pairs with present perfect (has/have + past participle) or present perfect continuous to show an action that started in the past and continues.

Tip: If you use since, check the verb — it usually needs “has/have been” or “has/have + past participle.”

4. Using simple past with ongoing actions and for incorrectly

Wrong: I lived here for five years. (when you still live here)

Right: I have lived here for five years.

Why: If the action continues to the present, use present perfect; simple past implies it finished.

Tip: Ask “Is this still true now?” If yes, use present perfect.

5. Confusing since (time) with since (because)

Example (cause): Since it was raining, we stayed home.

Example (time): I have been tired since Monday.

Why it’s confusing: Since can mean “because” or indicate a starting point. Context decides the meaning.

Tip: If you can replace since with “because” and the sentence still makes sense, it’s the causal since.

6. Omitting the time word after for in informal speech

Wrong/Unclear: I practiced for.

Right: I practiced for thirty minutes.

Why: For needs a duration phrase — minutes, hours, days, months, years, a long time, etc.

Tip: Always add a clear time unit after for.

7. Using since with vague or relative durations incorrectly

Wrong: She has been here since a long time.

Right: She has been here for a long time.

Why: A long time is a duration, not a start point. Use for.

Tip: Specific start = since; vague length = for.

8. Mixing up contracted forms in speech/ writing

Wrong: I’m here since 2010. (spoken: “I’m here…” implies present continuous)

Right: I’ve been here since 2010.

Why: Native structure for ongoing situations needs “have been” (present perfect continuous or present perfect).

Tip: Practice saying: “I’ve been + here/working/studying + since…”

9. Using for with a single moment (time point)

Wrong: He waited for 7 PM. (if you mean “from 7 PM onward”)

Right: He waited since 7 PM. (if waiting started at 7 PM and continues)

Why: For expresses a span; a single clock time is a starting point → use since.

Tip: Clock times (6 PM, 7:30) → usually since.

10. Overgeneralizing rules across tenses

Wrong: She will work here since 2022.

Right: She has worked here since 2022. / She will have worked here for three years by 2025.

Why: Since is tied to perfect aspect when describing an action from a past start to present. Future and other constructions need different forms.

Tip: Match since with perfect tenses when you mean “from then until now.”

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Conclusion

Understanding the difference between for and since is essential for speaking and writing English naturally and clearly. Both words are used to talk about time, but they serve different purposes. For helps you express the length or duration of time, while since tells you the starting point of an action that continues until now.

When you use them correctly, your sentences sound more accurate, confident, and professional. But when they are mixed up, the meaning becomes confusing and sometimes completely wrong.

The key to mastering for and since is simple:

• Use for with periods of time like minutes, hours, days, months, or years.

• Use since with a specific starting time like 9 AM, Monday, 2020, or “I was a child.”

Practice using them in your daily conversations, writing, and even while thinking in English. The more you use them, the more natural they will feel. With consistent practice and attention to these simple rules, you will be able to express time more accurately and avoid common grammar mistakes.