How do I withhold higher, and is this even legal any more?

[stacijingram]

I'm starting a new job next week, and I want to have the max withholdings allowed.  I noticed that single and married filing separately have the same withholding amount.  If I check this and later decide to file jointly because it better fits our situation (ie: is more beneficial), is that going to be a problem?  The new W4 no longer has the option of putting "married but withholding as single" and I'm afraid that with my husband's unemployment we could have a high tax bill this year.  I want to avoid paying in as much as possible, so I want to withhold at the highest rate.  Since I haven't started the job, form 505 is not helpful for me to figure out the extra amount to withhold, and I'd much rather do this with my withholding status.  Please help!

[Mike9241]

withholding more than required is not illegal.  you can even enter extra withholding in step 4 line 4(c) on the W-4. 

[TaxTim1]

@Mike9241 is correct.  It's not illegal to have more withheld.  Below are 2 articles re the fairly new W4 which offer some helpful guidance.  Hope this help.

https://turbotax.intuit.com/tax-tips/irs-tax-forms/form-w-4-and-your-take-home-pay/L4VSEhPez

https://turbotax.intuit.com/tax-tips/irs-tax-forms/what-is-a-w-4-form/L2NapDzX2

[Critter-3]

On the new W-4 form if you want to be withheld like the old married but withhold at the higher single rate option you simply click single on the new form. It's the exact same result as the old withholding form. Don't be afraid to click the single button even if you'll file a joint return later.  What you choose on the new W-4 form and what you do on the actual tax return do not need to be the same.