On the new form W-4, the larger the amount claimed for dependents on line 3 and the amount of deductions on line 4(b), the smaller the tax withholding will be.
So in theory, there is no amount on line 3 or 4(b) which will certainly reduce the tax withholding to 0 at any level of income.
Understood and thank you for reply. It would be fine if I get it "close enough" to $0. Here is the context for why I asked: I am putting $4,000 on line 3, because I only have two kids. Can I put more on that line even if I have only two kids? Because just putting $4,000 and using standard deduction will not get me close enough to $0 withholding that I need during partial pay layoff time due to virus. The only other place I can see reducing the withholding is line 4(b), but I don't plan to itemize, I will use the standard deduction, so it reads as if I shouldn't be putting anything there at all. When I look closer into Deductions Worksheet on pg. 3, there appears to be some logic involved that is not obviously stated, but can be deduced. The "If line 1 is greater than line 2, subtract line 2 from line 1. If line 2 is greater than line 1, enter “-0-” " effectively tells them the reason you are taking more than standard deduction (itemizing or interest/IRA stuff), but I don't know how this information factors in to what they do. I'm not itemizing, and I have minimal student loan interest paid each year, probably inconsequential.
So I don't want to "lie" to this form, but I need to reduce withholding. Do I put more on line 3 than I actually should? Or do I try to put something on line 4(b) and hope it has desired effect? In the past, I would have just jacked up the allowances to 10? and looked at result, trial and error. You can't do that as easily on new form.
The guidance you got regarding boxes 3 and 4(b) is correct. The higher that is, the less will be taken out. But I am concerned. You will be taxed on any money you get. Please be careful that you don't dig too deep of a hole.