Using Since and For Correctly

In our previous chapter, "Present Perfect vs Simple Past", we learned that the present perfect tense acts as a bridge connecting a past event to the present moment. It tells us that something started in the past and still matters right now.

But a bridge needs measurements. If an action started in the past and is still happening today, we naturally want to know: How long has this been going on? or When exactly did it start?

To answer these questions, English relies on two tiny but incredibly powerful words: For and Since.

At first glance, they seem to do the exact same job. In your mother tongue, you might even use the same word to translate both of them. However, in English grammar, they have strictly separate roles. Mixing them up is one of the most common mistakes students make, which is exactly why examiners love to test them in error-spotting and sentence-improvement questions.

By the end of this chapter, you will never have to guess between them again. You will understand the logic behind them, the specific tenses they demand, and the exact traps examiners set for you.

The Core Difference: The Measuring Tape vs. The Calendar Pin

To understand the difference between "for" and "since", you need to visualize how we look at time.

Imagine time is a long, straight road.

When you use For, you are holding a measuring tape. You are measuring a stretch of that road. You are counting the hours, the days, or the years that an action has lasted. You don't necessarily care what the clock said when it started; you only care about the total length of time.

When you use Since, you are holding a pin. You are dropping that pin on a specific date on a calendar or a specific hour on a clock. You are pointing to the exact moment the action was born. You aren't measuring the length of time yourself; you are just telling the listener when the clock started ticking.

Let us look at a quick example to see this in action:

• I have been studying for three hours. (Measuring tape: counting the hours. 1... 2... 3.)
• I have been studying since 9:00 AM. (Calendar pin: pointing to the exact start time.)

Both sentences might describe the exact same reality (if it is currently 12:00 PM), but they approach the time from two completely different angles.

Mastering "For" (The Duration)

We use "for" when we want to express the total amount of time an action has taken. If you can count the time in units, you must use "for".

Here are the common units of time we measure with "for":

• Seconds and Minutes: for ten seconds, for five minutes, for half an hour.
• Example: The kettle has been boiling for five minutes.
• Hours and Days: for two hours, for three days, for a fortnight (14 days).
• Example: It has been raining continuously for three days.
• Weeks and Months: for six weeks, for two months, for several months.
• Example: She has been training for the marathon for six months.
• Years, Decades, and Centuries: for four years, for a decade, for two centuries.
• Example: The British ruled India for nearly two centuries.

Vague Durations

Sometimes, we don't have an exact number, but we still want to express a block of time. "For" is used with these vague durations as well:

• for a long time (He has been waiting for a long time.)
• for ages (I haven't seen my college friends for ages.)
• for a while (Please sit here for a while.)
• for ever (It feels like we have been stuck in this traffic jam for ever.)

Mastering "Since" (The Starting Point)

We use "since" when we want to name the exact moment the action began. We are not counting the days; we are just pointing to the start line.

Here are the common starting points we point to with "since":

• Clock Times: since 8:00 AM, since noon, since midnight, since 4 o'clock.
• Example: The workers have been on strike since 6:00 AM.
• Days of the Week: since Monday, since Friday.
• Example: I have been feeling unwell since Tuesday.
• Dates and Months: since the 15th of August, since January, since October.
• Example: The new tax laws have been in effect since April.
• Years: since 1947, since 2010, since 2023.
• Example: My family has lived in this neighborhood since 1995.
• Festivals and Events: since Diwali, since Eid, since Christmas, since the wedding.
• Example: We haven't bought any new clothes since Diwali.
• Stages of Life: since childhood, since my youth, since birth.
• Example: They have been best friends since childhood.

The "Since + Clause" Rule (Highly Tested)

This is a favorite among examiners. "Since" doesn't just have to be followed by a time word like "Monday" or "2015". It can also be followed by an entire clause (a mini-sentence with its own subject and verb) that describes a past event.

When an event is used as a starting point, the verb inside the "since" clause must be in the Simple Past tense.

• Correct: I have been working here since I graduated. (Graduating is the starting point).
• Correct: She has not spoken to him since they had that argument.
• Correct: India has made massive technological leaps since it gained independence.

The Tense Connection: Why We Need Perfect Tenses

Now that we know the difference between the measuring tape (for) and the calendar pin (since), we need to talk about the verbs that go with them.

A very common mistake in spoken English is using "since" or "for" with the Present Continuous tense.

• Wrong: I am living in Delhi since 2015.
• Wrong: He is waiting for you for two hours.

Why are these wrong? Because the Present Continuous tense ("am living", "is waiting") only cares about right now. It has no memory. It cannot look back into the past.

If you want to talk about an action that started in the past and is still happening now, you need a tense that is built to stretch across time. You need the Present Perfect Continuous tense.

The Structure of Present Perfect Continuous

Subject + has/have + been + Verb(ing) + since/for + Time

• Correct: I have been living in Delhi since 2015.
• Correct: He has been waiting for you for two hours.

This tense perfectly matches the job of "since" and "for". The "has/have been" part builds the bridge from the past to the present, and the "since/for" part measures it.

What about the Present Perfect Simple?

Sometimes, we use the Present Perfect Simple (has/have + V3) with since and for. We do this in two situations:

1. 1Negative sentences: When we are talking about something that has not happened over a period of time.

• Example: I have not seen him since Monday. (We don't say: I have not been seeing him).

1. 1Verbs that cannot be continuous: Some verbs describe states of being, not actions. Verbs like know, own, believe, understand, be. These verbs hate the "-ing" form. (We will cover these deeply in the next chapter). Because they refuse to be continuous, they borrow the Present Perfect Simple instead.

• Example: I have known her for ten years. (Not: I have been knowing her).
• Example: He has been sick since yesterday. (Not: He has been being sick).

Common Exam Traps (Error Spotting)

Examiners know exactly how students translate sentences from their mother tongue into English, and they design their questions to catch those exact translation errors. Here are the three biggest traps to watch out for.

Trap 1: Using "From" instead of "Since"

In many Indian languages, the word for "from" and "since" is the same (e.g., se in Hindi/Urdu). Students often write:

• Incorrect: I have been studying here from 2020.

In English, "from" is used to show the start of an action in the future or in general routines, usually paired with "to" or "till".

• Routine: The bank is open from 9 AM to 5 PM.
• Future: I will start my new diet from Monday.

But if you are using a perfect tense to look back at an action that started in the past and continues to the present, you must use "since".

• Correct: I have been studying here since 2020.

Trap 2: Mixing up Since and For

Examiners will simply swap the words. They will put "since" next to a duration, or "for" next to a starting point.

• Incorrect: The committee has been debating this issue since five hours. (Five hours is a duration. You can count it. You need the measuring tape).
• Correct: The committee has been debating this issue for five hours.

• Incorrect: She has been the manager of this branch for October. (October is a name on a calendar. It is a starting point. You need the pin).
• Correct: She has been the manager of this branch since October.

Trap 3: The Simple Past Mismatch

Sometimes, the examiner will use "since" or "for" correctly, but they will put the main verb in the Simple Past tense.

• Incorrect: I lived in this city for ten years, and I still love it here.

If you say "I lived", it means the action is completely dead and finished. You don't live there anymore. But the second half of the sentence ("and I still love it here") proves you are still there. Therefore, the bridge to the present is still active.

• Correct: I have lived (or have been living) in this city for ten years, and I still love it here.

Step-by-Step Error Spotting Walkthrough

Let’s apply what we’ve learned to a typical exam-style sentence.

Example 1: Sentence: "The chief guest is speaking on the stage since 10:30 AM."

1. 1Spot the marker: "since".
2. 2Check the time: "10:30 AM". This is a clock time, a specific starting point. "Since" is the correct word here.
3. 3Check the main verb: "is speaking".
4. 4Analyze: "Is speaking" is Present Continuous. It cannot be used with "since". We need the Present Perfect Continuous to show an action starting in the past and continuing now.
5. 5Correction: "The chief guest has been speaking on the stage since 10:30 AM."

Example 2: Sentence: "My father has been working in the revenue department for he passed his graduation."

1. 1Spot the marker: "for".
2. 2Check the time: "he passed his graduation". This is not a duration. You cannot count "he passed his graduation" in numbers. It is a specific event in the past—a starting point.
3. 3Analyze: Because it is a starting point, "for" is the wrong word. We must use "since".
4. 4Check the tenses: The main verb is "has been working" (Present Perfect Continuous - Correct). The verb inside the clause is "passed" (Simple Past - Correct).
5. 5Correction: "My father has been working in the revenue department since he passed his graduation."

Quick Revision

Before you head into the exam, scan these high-yield points to lock the concepts in your memory:

• FOR = Duration. It measures the length of time (the measuring tape). Use it when you can count the time: for two days, for five years, for a long time.
• SINCE = Starting Point. It names the exact moment the action began (the calendar pin). Use it for names of times: since Monday, since 2018, since morning.
• The Tense Rule: Never use "since" or "for" with Present Continuous (is/am/are + ing). Always upgrade to Present Perfect Continuous (has/have been + ing).
• The "From" Trap: Do not use "from" to connect a past action to the present. Use "since". ("From" is for future plans or general routines).
• The Clause Rule: If "since" is followed by a full clause, the verb inside that clause must be in the Simple Past tense (since I arrived, since she left).
• State Verbs: Verbs that cannot take an "-ing" form (like know, own, be) use the Present Perfect Simple (has/have + V3) with since and for. (I have known him for years).