How to tell someone you want to stay friends, not date

Sometimes this is obvious. They said it directly or asked you out. Other times it's slower. They text you first most days, make plans just with you, bring you into their inner circle, or drop hints about the future. The sooner you clock that this has become one-sided, the sooner you can address it. Waiting six months while they build hope is unkind. The moment you know you don't feel the same way, that's your window.

Your reply needs to do two separate jobs. First, it has to be clear enough that there's no opening for them to misread it as a rain check. Don't say you need time, or you're not looking to date right now, or you need to focus on yourself. Say what you actually mean: you see this person as a friend, and that's all you see. Second, your message has to acknowledge what you actually value about them. You don't have to be effusive, but a one-liner about why they matter to you stops this from feeling like a full rejection of their person.

Text it soon, not tomorrow. Waiting days or weeks signals uncertainty you don't actually have. Send during the day when you're both likely to be thinking clearly. Don't do this in person unless you've already built up a strong foundation of friendship. After they read it, give them space. They may need a few days to process. If they don't reply within a week or respond with 'ok, I understand', take that as the answer. Don't reopen it by texting them again or asking if they're mad. If they come back with a long message about their feelings, you can reply once, but this isn't a conversation to litigate.