Trying to calculate ABV on a Monster Barleywine - with multiple additions

Trying to calculate ABV on a BIG Barleywine.  I have the OG and original volume.  There were multiple additions including concentrated wort, honey, sugar, syrup as well as a second pitch of yeast.

Is there a calculator or formula that I could use to somehow determine what the ABV of this beer is?

Sure.  Put your original ingredients and OG into any calculator, then enter all the additional ingredients, and adjust the attenuation to end up at your actual FG.  This should give you a new effective OG and ABV.  If you need help, provide everything to us and we (or at least I) can calculate it all out for you.

Thanks for the info.  Do you have a link to the best calculator for this type of process?

You could send it to a lab for testing, but that costs some money.