I find it weird that you can reduce charity contributions from taxation. Isn't it like grant for the rich to "choose where they pay their taxes"? And have nice dinners...
Correct me if I'm wrong, but I believe charity contributions can only reduce your taxable income. For simplicity, let's say you have an income of $1M and a tax rate of 35%. Normally you'd pay $350k in taxes. If you donate $100k to charity, then you pay 35% * $900k = $315k in taxes, for a total payout of $415k.
The real picture is a bit more complicated than that due to variable tax rates, but I don't think there's a case where donating to charity doesn't increase your total payout, since you give up 100% of what you donate instead of whatever tax rate you'd have paid.
