Mastering “Since” vs “For” in English | B1-B2 Guide

Introduction

Do you ever pause before choosing between since and for? You are not alone. Even advanced learners sometimes mix them up. Getting these two small words right is essential because they change the meaning of your sentence. In this guide, you will learn the simple rule, see plenty of examples, and avoid the most common mistakes.

What Is the Difference Between “Since” and “For”?

Both since and for are used to talk about time, but they answer different questions. Since tells us when something started. For tells us how long something lasted. Think of since as a starting point and for as a duration.

Rules

1. Use “since” with a specific point in time. This can be a date, a time, a day, a month, a year, or an event. Example: since 2010, since Monday, since 5 o’clock, since the party.
2. Use “for” with a period of time. This is an amount of time, such as hours, days, years, or centuries. Example: for three hours, for a week, for many years, for a long time.
3. “Since” is often used with present perfect or past perfect tenses. It marks the beginning of an action that continues to the present (or continued up to another past moment). Example: I have lived here since 2015.
4. “For” can be used with almost any tense. You can use it with present, past, future, and perfect tenses. Example: I studied for two hours. / I will stay for a week.
5. “Since” can also mean “because” (a different meaning, but common). In this post, we focus only on the time meaning.

How to Use It

Step 1: Identify the Time Expression

Look at the word or phrase that follows since or for. Is it a specific point or a duration?

• Specific point: last year, 1999, Tuesday, 8 AM, my birthday, the war ended → use since.
• Duration: two days, a month, five minutes, ages, a decade → use for.

Step 2: Check the Tense

While since almost always requires a perfect tense (present perfect or past perfect), for is flexible. However, when talking about an action that started in the past and continues now, both can appear in present perfect sentences.

• I have worked here since 2020. (starting point)
• I have worked here for four years. (duration)

Step 3: Test with a Question

Ask yourself: “When did it start?” → since. “How long?” → for.

Examples in Sentences

• She has been a teacher since 2015.
• They have lived in this house for ten years.
• I haven’t seen him since last Monday.
• We waited for three hours at the airport.
• He has studied French since he was a child.
• The company has been closed for a month.
• I have known her since we were in school.
• She has been feeling tired for several days.
• They have been married since 2010.
• I will be on vacation for two weeks.
• He has not called since Tuesday.
• We have been friends for over twenty years.

Common Mistakes

Mistake 1: Using “since” with a duration

❌ I have been waiting since three hours.

✅ I have been waiting for three hours.

Mistake 2: Using “for” with a specific point

❌ She has worked here for 2018.

✅ She has worked here since 2018.

Mistake 3: Forgetting the perfect tense with “since”

❌ I am here since morning.

✅ I have been here since morning.

Mistake 4: Using “since” with a future event

❌ I will stay here since next week.

✅ I will stay here for next week. (or: I will stay here from next week.)

Mistake 5: Confusing “since” (time) with “since” (reason)

❌ Since I was late, I missed the bus. (This is correct for reason, but if you mean time, it is wrong.)

✅ I have not seen him since he left. (time meaning)

Quick Summary

• Since = starting point (a specific time, date, or event).
• For = duration (a length of time).
• Since is usually used with present perfect or past perfect tenses.
• For can be used with any tense.
• Ask: “When?” → since. “How long?” → for.

Practice Exercises

Fill in the blanks with since or for.

1. I have known Maria ______ 2019.
2. They have been married ______ ten years.
3. We have not seen that movie ______ last summer.
4. She has been studying English ______ three months.
5. He has worked at the hospital ______ he graduated.

Answers

1. since
2. for
3. since
4. for
5. since

Conclusion

Mastering since and for is a small but powerful step toward more natural English. Remember the key: since = starting point, for = duration. Practice with the exercises above, and soon you will use them without thinking. Keep learning, and your English will keep improving!

FAQ

1. Can I use “since” with the past simple tense?

Generally, no. Since marks a starting point that continues to the present, so it requires a perfect tense (present perfect or past perfect). For example: I have lived here since 2010 (not I lived here since 2010). However, in informal spoken English, some native speakers might say It’s been two years since I saw him (which uses past simple in the “since” clause, but the main clause is present perfect).

2. What is the difference between “since” and “from”?

Since is used for a starting point that continues to the present (or a past reference point). From simply indicates a starting point without implying continuation. Example: I work from 9 AM to 5 PM (no continuation implied). I have worked since 9 AM (I am still working).

3. Can I use “for” with a specific time like “for 2020”?

No. For needs a duration, not a specific point. “2020” is a specific year, so you would say since 2020. If you want to talk about a period that lasts a whole year, you could say for a year or for the year 2020 (meaning throughout that year).

4. Why do we say “for ages” but not “since ages”?

“Ages” is a duration (a long period of time), so it requires for. Since ages is incorrect because “ages” is not a specific starting point. The correct phrase is for ages or since the age of… (if referring to a specific age).