Introduction
If you have ever paused mid-sentence, wondering whether to say “I have lived here since 2010″ or “I have lived here for 2010,” you are not alone. The words “since” and “for” are two of the most commonly confused time expressions in English, especially when used with the present perfect tense. Getting them right is essential for clear communication about duration and starting points. In this guide, we will break down the rules, show you how to use them correctly with various tenses, highlight common mistakes, and give you practice exercises to build your confidence.
What Is “Since” vs “For”?
At their simplest, “since” and “for” both talk about time, but they focus on different aspects. “Since” points to a specific starting point in the past — a moment, a date, or an event. “For” indicates a duration — how long something has been happening or lasted. Think of it this way: “since” answers when did it start?, while “for” answers how long?.
Rules
- Use “since” with a specific point in time. This includes dates (since 1999), times (since 2 o’clock), events (since the party), or ages (since I was ten).
- Use “for” with a period or duration of time. This includes lengths (for three hours, for five days), quantities (for a while, for a long time), or indefinite periods (for ages).
- Present perfect and present perfect continuous are the most common tenses with “since” and “for.” They connect the past to the present.
- “Since” can also introduce a clause. For example: “I have felt better since I started exercising.” Here, “I started exercising” is a full clause.
- “For” can be used with all tenses, not just the present perfect. For example: “I lived in Paris for two years” (past simple) or “I will study for an hour” (future).
- Do not use “since” with a duration. Saying “since three hours” is incorrect because “three hours” is a period, not a point.
- Do not use “for” with a specific point. Saying “for 2020” is incorrect because 2020 is a point, not a duration.
How to Use It
Follow these simple steps to choose correctly every time:
Step 1: Identify the time word or phrase.
Is it a specific point (e.g., Monday, 2015, the beginning of class) or a duration (e.g., two weeks, a few minutes, a long time)?
Step 2: Apply the rule.
- If it is a specific point → use since.
- If it is a duration → use for.
Step 3: Check the tense.
While “since” is most common with present perfect or present perfect continuous, “for” works with many tenses. For example:
- Present perfect: “She has worked here for five years.”
- Past simple: “She worked here for five years.”
- Future: “She will work here for five years.”
Step 4: Practice with “since” + clause.
When “since” introduces a full clause, the clause is usually in the past simple. For example: “I have been tired since I woke up.” The main clause uses present perfect, and the “since” clause uses past simple.
Examples in Sentences
- I have studied English since 2018.
- She has been a teacher for ten years.
- They have not visited us since last summer.
- He has lived in London for three months.
- We have been waiting since 9 a.m.
- The baby has slept for two hours.
- I have known him since we were children.
- She has worked at the hospital since 2015.
- He has been reading that book for a week.
- They have been friends since they met in college.
- I have not eaten anything for eight hours.
- We have owned this car since 2020.
Common Mistakes
- ❌ Mistake 1: “I have been here since three hours.”
✅ Correct: “I have been here for three hours.”
Reason: “Three hours” is a duration, not a specific point. - ❌ Mistake 2: “She has lived in Tokyo for 2019.”
✅ Correct: “She has lived in Tokyo since 2019.”
Reason: “2019” is a specific year (a point), not a duration. - ❌ Mistake 3: “He works here since 2010.”
✅ Correct: “He has worked here since 2010.”
Reason: “Since” requires a perfect tense (present perfect or present perfect continuous) to connect the past starting point to the present. - ❌ Mistake 4: “I have not seen her since a long time.”
✅ Correct: “I have not seen her for a long time.”
Reason: “A long time” is a duration, not a specific point. - ❌ Mistake 5: “They have been married for 2005.”
✅ Correct: “They have been married since 2005.”
Reason: “2005” is a specific year (point).
Quick Summary
- Since = a specific starting point in time (e.g., since Monday, since 1990, since I arrived).
- For = a duration or period of time (e.g., for two days, for a year, for a while).
- Use “since” mainly with present perfect and present perfect continuous tenses.
- Use “for” with any tense (past, present, future).
- If you can answer “When did it start?” → use “since”. If you can answer “How long?” → use “for”.
Practice Exercises
Fill in the blanks with either since or for.
- I have been learning Spanish ________ 2021.
- They have lived in this house ________ five years.
- She has not eaten anything ________ yesterday morning.
- We have known each other ________ a long time.
- He has worked at the company ________ he graduated from university.
Answers
- since (2021 is a specific year)
- for (five years is a duration)
- since (yesterday morning is a specific point)
- for (a long time is a duration)
- since (he graduated is a specific event/clause)
Conclusion
Mastering the difference between “since” and “for” will dramatically improve your accuracy in English, especially when using the present perfect tense. Remember the simple test: a specific point means “since,” and a duration means “for.” With regular practice and attention to time expressions, you will soon use these words naturally and confidently. Keep practicing, and do not hesitate to revisit this guide whenever you need a quick reminder.
FAQ
1. Can I use “since” with the past simple tense?
Generally, no. “Since” is used to connect a past starting point to the present, so it requires the present perfect or present perfect continuous in the main clause. However, “since” can introduce a clause in the past simple (e.g., “I have felt better since I started exercising”). The “since” clause itself is often in the past simple, but the main clause is in a perfect tense.
2. Is “for” ever used with the present perfect?
Yes, absolutely. “For” is very common with the present perfect to describe an action or state that began in the past and continues into the present. For example: “I have lived here for ten years.” The key is that “for” always introduces a duration, regardless of the tense.
3. What is the difference between “since” and “from”?
“Since” is used to indicate a starting point that continues to the present (often with perfect tenses). “From” indicates a starting point but does not imply continuation to the present. For example: “I work from 9 a.m. to 5 p.m.” (a routine) vs. “I have worked here since 9 a.m.” (still working now). “From” is often paired with “to” or “until.”
4. Can I use “since” with future tenses?
No, “since” is not used with future tenses because it refers to a past starting point that connects to the present. For future time expressions, use “from” or “starting.” For example: “I will be on vacation from next Monday” (not “since next Monday”).