Since vs For: How English Expresses Time Clearly

Even learners who already use the present perfect often hesitate when choosing between since and for. The structures seem simple, yet mistakes appear frequently in speaking and writing.

The problem is not grammar difficulty. Instead, it is about how English sees time. Once you understand that perspective, choosing between since and for becomes much easier.

This explanation connects directly to the broader tense logic presented in: Present Perfect Explained: When English Connects the Past to the Present

The Core Difference Between Since and For

The real difference between since and for is not the verb tense. It is how time is described.

• Since points to the moment something started
• For measures how long something has lasted

Both are frequently used with the present perfect because this tense connects past actions to the present moment.

Using For: Thinking in Duration

Imagine that now is 2025.

You say:

I have lived in Manchester for two years.

When you use for two years, you are not saying when the action started. You are only measuring the length of time.

However, logically, if it is 2025 and you have lived there for two years, this means you started living there around 2023.

English does not require you to say 2023. The listener understands that automatically.

That is why for is used when the exact starting point is not mentioned, only the duration.

More examples:

She has worked at this company for five years.
They have been married for a long time.

In all these cases, the action started in the past and is still true now.

Using Since: Naming the Starting Point

Now imagine the same situation, but you choose to say when it started.

You say:

I have lived in Manchester since 2023.

Here, the duration is not mentioned directly. Instead, you give the starting moment. The listener can calculate the length of time if needed.

More examples:

She has worked at this company since 2018.
They have known each other since university.

This is why since always needs a specific moment in time.

Seeing the Difference Clearly

These two sentences describe the same reality, but from different angles:

I have lived in Manchester for two years.
I have lived in Manchester since 2023.

The situation is identical. The choice depends on whether you want to emphasize duration or starting point.

Once learners understand this, confusion disappears.

Since and For with Ongoing Actions

Because since and for describe time that continues until now, they are very common with the present perfect continuous.

Examples:

I have been studying English for two hours.
She has been feeling tired since last week.

The verb highlights the activity, while since and for explain how time passes.

Where Have Been and Have Gone Fit In

At this point, many learners notice that English also uses have been and have gone when talking about experience and duration.

For example:

She has been in Manchester for two years.
She has gone to Manchester.

These forms affect the meaning of where the person is now, not how time is measured.

If you want a focused explanation of that difference, see
 Have Been or Have Gone? Learn the Difference Once and for All

Understanding this distinction helps make sentences with since and for even clearer.

Why Since and For Cannot Be Swapped

Learners sometimes try to change since to for, but English does not allow that.

Compare:

I have lived here since two years.
This sounds wrong because two years is not a starting point.

Correct:

I have lived here for two years.

Now compare:

I have lived here for 2023.
This sounds wrong because 2023 is not a duration.

Correct version:

I have lived here since 2023.

The logic is always the same.

One Question That Always Works

When choosing between since and for, ask yourself:

Am I talking about when it started or how long it has lasted?

That single question solves most doubts.

Conclusion: Since and For Are About Perspective on Time

The difference between since and for is not about memorization. It is about how the speaker frames time.

For measures the duration from past to present.
Since anchors the action to a specific starting point.

This topic is a key part of the present perfect system and works together with ideas like have been, have gone, and ongoing actions. To see how all these elements connect, return to: Present Perfect Explained: When English Connects the Past to the Present

Source: ef education first, bbc