Present Perfect vs Past Simple: What vs When

1 The Names Tell You Everything: PRESENT Perfect vs PAST Simple

Here’s the secret: the answer is in the names themselves.

Present Perfect is a PRESENT tense. It tells you WHAT happened, not exactly WHEN it happened. Look at this sentence: ‘I have eaten.’ This is complete. It tells you about an action, and the result connects to now. You are not hungry now because you have eaten. You don’t need to say when. Similarly, ‘I have won the jackpot’ is good news!

But Past Simple is different. It is a PAST tense. It always needs two pieces of information: WHAT happened and WHEN it happened. Look at this: ‘I ate.’ This sentence is not complete. Your listener immediately thinks: ‘When? When did you eat?’ You must add the time: ‘I ate an hour ago’ or ‘I ate at 7pm’ or ‘I ate before the meeting.’ Unfortunately, ‘I won the jackpot’ is old news, in fact it’s not news at all

This is the most important rule on this page. Present Perfect = WHAT happened (time is not important or not specified). Past Simple = WHAT happened + WHEN it happened (time is always important).

Past Simple can talk about any past time, even one second ago: ‘I finished it a moment ago.’ But Present Perfect can talk about your entire life: ‘I have been married’ (this tells us WHAT, not when). When we say ‘I have been married,’ we probably mean we are not married now. The marriage was at some point in our life, but we don’t say when. If we add ‘when,’ everything changes: ‘I was married in 2010’ (Past Simple, because we said WHEN).

2 Past Simple: The Time Markers You Must Know

You know how to form Past Simple. At B1 level, this is not new. But let’s be very clear about the time reference words that go with Past Simple. These words tell you WHEN something happened. They point to a closed, finished time period.

Here are the most common ones: yesterday, last (last week, last month, last year), ago (two days ago, five minutes ago), in + finished year (in 2020, in 1999), on + specific day (on Monday, on 15th March), at + specific time (at 3pm, at midnight), when (when I was a child, when I lived in Paris), then, and past time phrases like ‘during my university years’ or ‘in those days.’

Every single one of these time markers points to a finished moment or period. That moment is separate from now. It is closed. And that’s why they work with Past Simple.

3 Present Perfect: Open Time and Life Experience

Present Perfect is more flexible about time. It works with open time periods — periods that include NOW, the present moment. It also works when we don’t mention time at all, because the focus is on WHAT happened, not WHEN.

Let’s look at two examples that show the difference clearly:

1. ‘I have been married.’ (This means: at some point in my life, I was married. We don’t know when. We probably think the person is not married now.)

2. ‘I have been married since February 2025.’ (This means: I got married in February 2025, and I am STILL married now. The time period started in the past but continues to now.)

Notice the difference? In sentence 1, we talk about life experience. No time is mentioned. In sentence 2, we use since to show the time period is still open — it reaches from the past to now.

Present Perfect works with these time reference words: since (since Monday, since 2020), for (for three weeks, for ages), this + time period (this week, this year, this morning if the morning is not finished yet), so far, already, yet, just, recently, ever, never, up to now, until now.

All of these words point to time periods that are open (they include now) OR they don’t specify exactly when. That’s why they work with Present Perfect.

4 How Not to Make Mistakes: The Battle Between Words and Grammar

English is a lexically driven language. This means the words you choose control the grammar you must use. When your time reference word says ‘finished time,’ you cannot use Present Perfect. When your time reference word says ‘open time’ or you don’t mention time at all, you cannot use Past Simple (in most cases).

Let’s look at the most common mistakes learners make, and why they happen.

Mistake 1: Using Present Perfect with finished time words
✗ ‘I have seen him yesterday.’

Why? ‘Yesterday’ is a finished time. It is closed. Past Simple is required.

✗ ‘I have spoken to him five minutes ago.’

Why? ‘Ago’ always means finished time. Use Past Simple.

✗ ‘When have you started your job?’

Why? ‘When’ asks for a specific finished time. Use Past Simple.

Mistake 2: Using Past Simple with open time or present result
✗ ‘I went to London this week.’

Why? ‘This week’ is not finished yet. It includes now. Use Present Perfect.

✗ ‘I just finished it.’

Why? ‘Just’ shows a very recent action with a result that matters now. Use Present Perfect.

✗ ‘I lost my keys, so I cannot get into the house.’

Why? The focus is on the present result (I cannot get in NOW). Use Present Perfect.

Mistake 3: Form errors
✗ ‘She been to Spain.’

Why? Never forget ‘have’ or ‘has’ in Present Perfect.

✗ ‘I have went there before.’

Why? The past participle of ‘go’ is ‘gone’ or ‘been,’ not ‘went.’

✗ ‘Did you have ever tried sushi?’

Why? Never use ‘did’ with Present Perfect. Use ‘have/has.’

Mistake 4: Mixing time markers incorrectly
✗ ‘I have visited Paris in 2019.’

Why? ‘In 2019’ is finished time. Use Past Simple.

Remember: when you choose your time reference words, you choose your tense. The words and the grammar must work together. If they fight, your sentence loses.

5 Practice Task: Your Professional Update

Now use both tenses in one piece of writing. Remember: Past Simple = WHAT + WHEN. Present Perfect = WHAT (without saying exactly when, or with open time periods).

6 Recap: The WHAT vs WHEN Rule

Let’s bring everything together.

Present Perfect is a PRESENT tense. It tells you WHAT happened. It does not tell you exactly WHEN. The sentence ‘I have eaten’ is complete because Present Perfect is interested in the action and its connection to now, not the specific time. Present Perfect works with OPEN time periods (this week, since Monday, so far) or with no time reference at all (ever, never, already, yet, just).

Past Simple is a PAST tense. It always needs WHAT and WHEN. The sentence ‘I ate’ is not complete — your listener needs to know when. Past Simple works with CLOSED, FINISHED time periods (yesterday, ago, last week, in 2020, at 3pm, on Monday, when I was young).

English is lexically driven. Your choice of time reference words controls your grammar. If you say ‘yesterday,’ you must use Past Simple. If you say ‘this week’ (and the week is not finished), you must use Present Perfect. When words and grammar fight, there are no winners — only confused listeners.

Master this distinction, and you will make rapid, confident decisions about which tense to use. Think: Am I saying WHEN (finished time)? Use Past Simple. Am I saying WHAT (without specific time, or with open time)? Use Present Perfect.

That’s the rule. Now you know it.