Since vs For: Simple Explanation for English Learners

If you are learning English, the difference between since and for is simple: use since with a specific point in time (when something started), and use for with a duration of time (how long something lasted). This is the core rule, and once you understand it, you will avoid the most common mistakes with these two words.

Quick Answer

Since = from a starting point until now. Example: I have worked here since 2019.

For = a length of time. Example: I have worked here for five years.

Think of since as pointing to a calendar date or event, and for as measuring a period.

When to Use Since

Use since when you want to mention the exact moment or event when something began. This moment is a fixed point in the past. It can be a year, a month, a day, a time, or even a past event.

Examples with Since

• I have been a teacher since 2015.
• She has lived in London since last June.
• They have been friends since they were children.
• He has not eaten anything since breakfast.
• We have owned this car since 2018.

Notice that since is almost always used with a perfect tense (present perfect or past perfect). The action or state started in the past and continues to the present.

When to Use For

Use for when you want to talk about the total length of time an action or situation has lasted. This is a duration, not a starting point.

Examples with For

• I have been a teacher for nine years.
• She has lived in London for one year.
• They have been friends for a long time.
• He has not eaten anything for six hours.
• We have owned this car for five years.

Like since, for is very common with perfect tenses. However, you can also use for with other tenses when talking about past or future durations. For example: I will stay here for two weeks.

Comparison Table: Since vs For

This table shows the simple difference. If you can answer “when did it start?” use since. If you can answer “how long?” use for.

Natural Examples in Context

Seeing these words in real situations helps you remember them. Below are examples from different contexts.

In Conversation

• Friend A: How long have you been waiting?
  Friend B: I have been waiting for twenty minutes. (duration)
• Friend A: When did you arrive?
  Friend B: I have been here since 3 o’clock. (starting point)

In Email

• Dear Mr. Chen, I have been working on your account since Monday morning. I will have an update for you by the end of the day.
• We have not received a payment since last month. Please send the overdue amount for the past three months.

Formal vs Informal Tone

Both since and for are neutral and can be used in any situation. However, in formal writing, you might see since used to mean “because” (e.g., Since you have not replied, we will cancel the order). This is a different meaning. In this article, we only focus on the time meaning. In informal conversation, people often shorten sentences: “I haven’t seen him since Tuesday.” This is perfectly natural.

Common Mistakes with Since and For

Even advanced learners sometimes confuse these two words. Here are the most frequent errors.

Mistake 1: Using “since” with a duration

Incorrect: I have worked here since three years.
Correct: I have worked here for three years.

Remember: “three years” is a duration, not a starting point.

Mistake 2: Using “for” with a specific point

Incorrect: I have worked here for 2020.
Correct: I have worked here since 2020.

Remember: “2020” is a specific year, a starting point.

Mistake 3: Forgetting the perfect tense with “since”

Incorrect: I am here since 9 AM.
Correct: I have been here since 9 AM.

When you use since to talk about something that started in the past and continues, you need a perfect tense (have been, has lived, etc.).

Mistake 4: Using “since” for future time

Incorrect: I will wait since 5 PM.
Correct: I will wait from 5 PM. (or until 5 PM, depending on meaning)

Since is not used for future starting points. Use from instead.

Better Alternatives and When to Use Them

Sometimes you can replace since or for with other words to change the tone or meaning.

Instead of “since”

• From: Use when talking about a starting point in the past, present, or future. Example: I work from 9 to 5. (This is more neutral than since 9 which implies continuing.)
• Starting: Use in more formal or written contexts. Example: The policy is effective starting January 1st.

Instead of “for”

• During: Use when something happens within a period, not necessarily the whole time. Example: I slept during the movie. (Compare: I slept for two hours.)
• Over: Use to emphasize the whole period. Example: Over the past year, sales have increased.
• Throughout: Use for continuous action in a period. Example: He worked throughout the night.

Choose these alternatives when you want to be more precise about the relationship between time and action.

Mini Practice: Since or For?

Test yourself. Choose since or for for each sentence. Answers are below.

1. I have studied English ______ 2018.
2. She has been a doctor ______ ten years.
3. They have not seen each other ______ last Christmas.
4. We have lived in this house ______ a long time.

Answers

1. since (2018 is a specific year)
2. for (ten years is a duration)
3. since (last Christmas is a specific event)
4. for (a long time is a duration)

If you got all four correct, you understand the rule. If you made a mistake, review the comparison table above.

Frequently Asked Questions

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

Yes, but only when the action is finished. For example: I saw him since Monday is incorrect. However, It has been three years since I saw him is correct. In this structure, since introduces a clause with a past simple verb, but the main verb is in the present perfect.

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

Since always connects the past to the present. From simply marks a starting point and can be used for past, present, or future. Example: I work from 8 AM (could be every day). I have worked since 8 AM (means I started at 8 and am still working now).

3. Is “for” always used with perfect tenses?

No. You can use for with any tense. Examples: I will stay for a week (future), I walked for an hour (past simple), I am studying for two hours (present continuous). However, when you mean “from the past until now,” the present perfect is most common.

4. Can I end a sentence with “since” or “for”?

Yes, in informal English. Example: How long have you been here? I have been here since 2 PM. You can also say: I have been here since. This is casual and understood. For for, you can say: I have been waiting for hours. Ending with for alone is less common but possible in very informal speech: How long? For.

Final Tip

When you are writing an email or speaking and you are not sure, ask yourself: “Am I giving a starting point or a duration?” If you can replace the word with “from [time] until now,” use since. If you can replace it with “a period of [time],” use for. Practice with real sentences from your own life, and soon it will feel natural.

For more help with similar word pairs, visit our Beginner Comparison Guides or explore other Grammar Word Differences.