Pre 2018 or post are the same for how the deduction is a deduction and not a credit. That is to say that on w2 income you will pay payroll tax and on 1099 you

Pre 2018 or post are the same for how the deduction is a deduction and not a credit. That is to say that on w2 income you will pay payroll tax and on 1099 you may pay self employment tax -- in addition to income tax. You then get to deduct the income tax only. So the presented case, to get paid a small sum as a contractor that either you or the company will donate to a charity; it's going to be a net 0 or net negative to take the income and then donate it 100% compared to letting the company donate it. The relevant changes were to the standard deduction and the % cap (if you're donating >50% of your income). Technically, the standard deduction doesn't matter here at all, that's a choice, it would be a net negative for the filer to choose itemized over the standard if they don't exceed the standard. The 2018 changes also effect the pass through rate, so there is a small possibility that if you took payment in your pte, you'd be taxed at 21% cap, your business didn't make enough to pay self employment tax, and then you donate the money from your normal earned income at the 22 or 24% rate.