What would the inheritance tax be on a million dollars?

Current US estate tax for values over $500,000 is $155,800 for the first $500,000, and 35% of the amount in excess of $500,000. In this case that would be $155,800 + $175,000, totalling $330,800. Obviously this is a simplified calculation; the actual paperwork involved is significant, but can lower the amount of tax.