Present Perfect with For and Since

This grammar works by measuring time. It looks at an action and asks: "When did this start?" or "How long has this been going on?" We use for when we want to talk about a duration. This is a specific block of time like three hours or ten years. We use since when we want to talk about a starting point. This is a specific moment like 8:00 AM or last Tuesday. It is like looking at a calendar. Since points to one specific date with a big red circle. For draws a long line across many days. Native speakers use these to avoid confusion. If you tell a date, use since. If you count the units of time, use for. It is simpler than choosing a Netflix movie on a Friday night, I promise.

1. 1Building this sentence is like following a simple recipe. You only need four main ingredients.
2. 2Start with your Subject. This is the person or thing doing the action (e.g., I, She, They).
3. 3Add the helping verb. Use have for I, you, we, and they. Use has for he, she, and it.
4. 4Use the Past Participle. For regular verbs, just add -ed. For irregular ones, you might need to check a list (e.g., been, known, seen).
5. 5Finish with for or since and the time expression.
6. 6Example: I (Subject) + have (Helping verb) + worked (Past participle) + for + six months (Duration).

Use this pattern when an action is not finished. You started a job in 2020. You still work there today. You say: "I have worked here since 2020." This is perfect for job interviews. It shows stability and experience. Use it when talking about relationships too. "We have been friends for a decade." This sounds much warmer than just saying "We met ten years ago." It implies the friendship is still strong. You can also use it for negative situations. "I haven't eaten since breakfast." This explains why you are currently grumpy and looking at your friend's sandwich. It connects your past hunger to your current mood. Use it for states of being with verbs like be, know, or like. These verbs often describe things that last a long time.

Do not use this for actions that are completely over. If you finished your coffee ten minutes ago, do not use since. Use the Past Simple instead. "I drank my coffee." Also, do not use since with a duration. You cannot say "since five hours." That is a grammar traffic jam. Similarly, do not use for with a specific date. "For 1995" sounds very strange to an English ear. Avoid using this tense with specific finished time markers like yesterday, last week, or in 2010 unless they follow the word since. If you say "I have seen him yesterday," a grammar fairy loses its wings. Stick to the Past Simple for specific finished moments.

Yes, even people who have spoken English for years mess this up sometimes. The biggest mistake is using the Present Simple with since. You might want to say "I am here since Monday." This is a classic error. In English, we must use the Present Perfect: "I have been here since Monday." Another common slip is mixing up for and since. Remember: for is for counting, since is for naming. Don't say "for I was a child." Say "since I was a child." Also, watch out for the word ago. We never use since and ago together. "Since two years ago" is redundant. Just say "for two years" or "since 2022." It keeps your sentences clean and professional.

People often confuse this with the Past Simple. Think of the Past Simple as a photo. It is a frozen moment in the past. "I lived in Paris." (I don't live there now). Think of the Present Perfect as a video. it is still playing. "I have lived in Paris for a year." (I am still in Paris). Another contrast is with the Present Perfect Continuous. We use I have been working for active, messy tasks. We use I have worked for more permanent states. For B1 level, focusing on the "still true" aspect of the Present Perfect is your best bet. It is the difference between "I lost my keys" (maybe I found them?) and "I have lost my keys" (I am standing outside my house in the rain right now).