What's the best way to tell my friends that I self harm without them telling anybody?

Don't tell them. They don't have to know. It's something really private so if you want help go with a professional.

Self-harming is a personal thing and opening up to people can be scary. Finding the right time to tell people you self-harm can be the most difficult part, but only you will know the right time and the right people. Try asking yourself, are your friends trustworthy, have you ever told them something serious and they spread it to others, are they supportive? I think once you get the answers to these types of questions, you will fine your answer.

You know your friends better than I do, but you could just try telling them you don't want anybody to know? I know it seems simple, but if they're trustworthy, they won't tell anyone!

I personally have had to tell my friends some pretty bad things in the past(not self harm, but other embarrassing or otherwise unusual topics), and to be honest, some of them did share that information with other people. I was crushed that my friends would do that. The first thing you have to do is find the friends that you would trust with your life, and have a 1 on 1 sit down with them. Don't do it over texting, and don't do it in a group discussion. Make it a personal 1 on 1 face to face conversation. This will help communicate verbally and non-verbally how sensitive and how personal/important this issue is to you and hopefully show your friend(s) of choice that you really care about this and you really care about them.

Find out their views on it first, see if it makes them uncomfortable, so on and then base it off there,

You should tell them that you would be grateful for their support but that it would make you feel stresed out and exposed if people would know about your problem without you yourself having decided to tell them. Tell them that if they want to help you they have to respect your privacy and not tell anyone else. If they think you need more help, you can still agree to go to a councellar with them or something similar. They can support you but not take away your right to make your own decisions. Good luck x

You can't really be sure they will not tell to someone else, and if that happens it surely isn't your fault. I used to self harm and I never told anyone because I was really ashamed and afraid that if somebody would know then the word would spread and some actions would have been made. Then, after years, I told a friend..and then another..and another. I find people to be so much more understanding that I could ever imagine. It wasn't easy, and I took my time. You should never do something you don't feel up to. Tell only to the people you trust and you're comfortable with. Test the ground. Try to understand how that makes you feel and take your time doing that. That's the only "right" way to do it.

When I told my friends I said "I really need you guys to listen, I self harm" then they were like what?why? I also said they couldn't away to anyone because I am really insecure about it.

As frustrating as it is, your friends may tell someone about your self-harming. More importantly you should ask yourself why you are self-harming and if you are in danger. It is difficult for a friend to bear the weight of sadness by themselves, just like it is difficult for you to do the same. Consider talking to an adult friend who may have more life experience in this type of self harm.

you need to be sure you can trust them and before telling them you self harm tell them about your situation and how it is all making you feel and say that due to all of that you have started selfharming