W4 Adjustments

[someonesomewhere]

Need some help with figuring out my W4 (for full-time job) based on my wife's W4 (part-time job)

Federal W4

I work full time and Mrs is starting part time job (~20 hour per week) while doing full time college.  When doing her W4s I followed IRS' advice and put her allowance and additional amount (line 5 and 6) as Zero and selected Married as filing option. 

Now do I decrease my allowances by 1 for her or can I keep that at current number?

State W4

Similar scenario as above but this time state. On her W4 I put in ZERO for all the fields.  

Now on my W4 do I decrease her as a dependent by 1? 

Or recommended route is to keep the current values on both my W4s until 1/1/19? 

Thanks in  advance.

[Carl]

The less exemptions you claim on your W-4, the more taxes that will be withheld from each paycheck. That means at tax filing time you will most likely not owe additional tax, and will most likely get some of the withheld taxes refunded to you. If you claim more exemptions, then less tax will be withheld from each paycheck. That will increase the possibility of owing additional tax at tax filing time.

I can't speak for state taxes. But for federal taxes it's important to read the instructions carefully. If you don't read the instructions then it's perfectly possible that you will claim more exemptions than you are entitled to, and will end up owing more tax at tax filing time.

If your employer did not provide you instructions with the new W-4, (they should have) you can get them yourself at https://www.irs.gov/pub/irs-pdf/fw4.pdf  One common mistake I see that indicates the instructions were not read, is if an excemption is claimed in box E and the tax file does not have a qualifying dependent under the age of 17 on Dec 31 of the tax year. So please read the instructions for your own sake, and if your dependent will be turning 17 on or before Dec 31 of 2018, they do not qualify you for that specific exemption.

[someonesomewhere]

Thanks for replying and the detailed publication link https://www.irs.gov/pub/irs-pdf/fw4.pdf 

We do not have any exemptions.  So, should be good on that front.  What was confusing me was Multi Job Worksheet, which says below, on page 2 (https://www.irs.gov/pub/irs-pdf/fw4.pdf).  Hence my comment about putting ZEROs in wife's Federal W4 and trying to figure out numbers on my W4.  Reading the 505 Publication should help. 

Figure the total number of allowances you’re entitled to claim and any additional amount of tax to withhold on all jobs using worksheets from only one Form W-4. Claim all allowances on the W-4 that you or your spouse file for the highest paying job in your family and claim zero allowances on Forms W-4 filed for all other jobs. For example, if you earn $60,000 per year and your spouse earns $20,000, you should complete the worksheets to determine what to enter on lines 5 and 6 of your Form W-4, and your spouse should enter zero (“-0-”) on lines 5 and 6 of his or her Form W-4. See Pub. 505 for details.

Thanks for your help again.

[Carl]

That just means your wife's income will have withholding at a higher rate percentage-wise is all, which in my opinion (and we know what opinions are like.) is the safest way to go.