You need a polite version.
Okay, there could be several ways to tell that.
Here are a few alternatives to 'none of your business' that come to my mind.
I think I can tackle it in my own ways
I don't think I need help
, I can handle it well Thanks for the suggestion, but no thanks To me, these are less severe than telling 'none of your business' straightforwardly.
ell.stackexchange.com/users/3187/Maulik V
What's it to you?
Why, what's it to you?
How is this any of your business?
Why are you so concerned?
Don't worry about it.
(This is actually very obnoxious if you think about, but many people fail to notice the connotation).
You don't need this.
Take your pick.
ell.stackexchange.com/users/27173/Ricky
While I agree with you that "It's none of your business" is rather terse and can be seen to be impolite, I don't think there is a single phrase that literally means the same but is seen more formal and polite.
A short explanation why a question is off limits, however, allows the conversation (or the person asking) to move on.
You can give a vague, one or two word answer to the question to close the issue, but you probably won't have to.
ell.stackexchange.com/users/27395/gnyrinn
The situation you are dealing with will have a lot to do with what polite terms will work.
My favorite is "I appreciate your offer to help, but I need to work on this on my own for now."
ell.stackexchange.com/users/27403/Bill Linder
This is none of your concern.
This is not relevant to you.
This probably isn't relevant to you.
(softer)
ell.stackexchange.com/users/16353/Stumbler
The title really sounds silly but it is  true  translation from local language to English. I believe (and sure) it's not correct.  Can someone suggest to me the correct word (phrase)?  The intention is: "Its not your business".  The context: dialogue between two school children. The point is, one meddles in other's business.
Translation of "Why for you". (Softer, politer synonyms for "It's not your business")
ell.stackexchange.com
<phrase-request><politeness>
ell.stackexchange.com/questions/75223
ell.stackexchange.com/users/None/
"What's it to you?", "How is this any of your business?", "Why are you so concerned?" and "Don't worry about it" are all suggested alternatives to "It's not your business" There are no perfect alternatives, though you could use 'what's it to you', why are you so concerned' and 'don't worry about it'.
There are no perfect alternatives, though you could use 'what's it to you', why are you so concerned' and 'don't worry about it'.