Didn't realize LLC needed an EIN. LLC formed four years ago

[homeostatsis]

Formed LLC four years ago with a friend.  It is dormant, no business and no revenue since inception.  Misread and thought I didn't need to file for an EIN since we have no employees, etc.  The LLC is not doing anything, it's just there.  Should we get an EIN now and is it too late?  Will we face a bad tax penalty for not knowing this? Not sure what to do now that it's so after the fact.  thanks  

[M-MTax]

If the LLC has had no income nor deductions since inception, it doesn't matter much since the LLC would not have been required to file a return to date - even if it had an EIN.

[SusanY1]

It's not too late, if you wish to acquire an EIN for when the LLC is active.  Instructions for how to do this are HERE.   You can apply online in a matter of a few minutes but keep two things in mind if you do.  First, it does not cost anything to apply.  If you're asked for payment, you're not on the official site.  Second, the EIN "letter" will display on the screen and you need to print a copy or create a PDF and save in a safe place - it's your only proof of the EIN assigned to you.  

As M-MTax pointed out it's not a concern that you didn't have it before now since there has been nothing to report.