You pay the entire amount in the bracket you fall into. At $600,000, you also are subject to the medicare surcharge of 3.8%, so you’re going to pay 23.8%, which equates to $142,800.

For example, say for 2024 I have 600,000 in long term capital gains, do I pay zero for the first 47,025 long term capital gains, then I pay 15% rate the next 47,025 to 518,900, then 20% rate for the remaining (600,000-518,900=81100, OR do I pay the whole 600,000 long term capital gains at 20%?????

If this is a long term capital gain, you’re in the 15% bracket unless your income is over the limit for your filing status.

You also don’t have to pay estimated taxes unless you don’t withhold enough to cover your previous year’s tax bill. Many people with one-time gains opt to just wait until tax filing to pay any tax due. No reason to give the IRS any extra money early.

tell that to Mitch Romney, how does he loop hole it