Is prepaying by Tax by CC only allowable for those who need to file a 1040-ES due to their primary income not being from an employer, i.e., those self-employed? Can the same thing be done for those who normally would have withholding deducted from their paycheck? Can they just deduct any quarterly payment from on line 3 of their W-4 and pay less or no witholding4?
Assuming it is allowed, are the taxes on that income only due at the end of the quarter? Those subject to withholding usually pay with every paycheck. Does paying quarterly effectively allow you to postpone paying taxes on your first paycheck from immediately to three months later?