On the 2021 W-4, does the deduction amount entered include the standard deduction?

Question

I'm setting up my federal tax withholdings with my employer for 2021 using the new W4 form. I'm confused about line 4b. Based on the tax as accurately as I can figure it, if I select married-filing-jointly and figure in the $4000 in tax credits I know I am due on line 3, I will end up overpaying my taxes.

To make it come out just right (my goal here is to break even with the IRS - no refund, no bill to pay in April) I need to plan on having about $1000 in additional deductions annually. Not credits, but additional deductions. So, I'd like my W4 to reflect...

• MFJ
• Standard deduction
• about $1000 in additional, annual deductions above and beyond the standard deduction.

Do I write in this amount, $1000, for line 4B? Would my employer then compute my taxable income as as my gross income, minus standard deduction, minus this $1000? And then they would compute the tax, subtract the $4000 tax credits and divide this final amount over the number of paychecks?

My worry is that I've figured it wrong and this $1000 appears to be my "total" deductions in place of the standard deduction, resulting in overpaying massively on my first paycheck.

Answer 1

On Line 4(b) of the new Form W-4, it says,

Deductions. If you expect to claim deductions other than the standard deduction and want to reduce your withholding, use the Deductions Worksheet on page 3 and enter the result here

Looking at the Deductions Worksheet on page 3, it has you entering in your expected total Schedule A (itemized) deductions, subtracting the amount that your standard deduction would be, then adding in the amount of your above-the-line deductions (from Schedule 1, Part II), such as IRA or HSA contributions. This is the number that you enter on Line 4(b).

So if you expect to have $1000 more in itemized deductions than your standard deduction would be ($25,100 for Married Filing Jointly in 2021), or if you expect to have $1000 in above-the-line deductions in addition to the standard deduction, the instructions would have you enter $1000 on Line 4(b).