Oh...my favorite topic. Taxes.
I have struggled with the exemptions number over the years because of changes in my deductions (as others have noted).
What has worked best for me is to look at how much I got back the previous year, and if it is more than $1,000 I increase my exemptions by 1. Opposite is also true....if I owe more than $1,000 (or multiples of $1,000) then reduce exemptions by that multiple.
That is the rule of thumb for me. (yours may vary slightly) That W-4 form is pretty impossible to decipher.
As an example, my daughter just got her first full time, after college job. So the employer says just fill out this W-4. My daughter looked at it and immediately called me saying 'what does all this mean?', referring to the forms various line items.
I told her, just put 1....for yourself.. and sign the form. She was skeptical and said what about all these other things? I told her that they would all be 0 for her. She still wasn't convinced. So I said, OK, start reading the list to me. Most of them I cut her off before she even finished the item because I knew she didn't meet the criteria. (Just starting out, single, only income from salary, no exemptions for any of the additional things.) Even her 401K would not affect taxes because she was 100% Roth.
Anyway, hope that can give you an alternate method for your exemptions, that is not too cumbersome. By the way, you gotta do the same thing for State taxes if you are fortunate to be like me and live in a State that has State Income Tax. (It will likely be different!) :Eyecrazy: