If someone gift me 1 million dollars what would the gift tax be and who would pay it?

Donor pays gift tax so person who gave you gift, but there is a lifetime exclusion of over $5 Million right now so unless they have exceeded that no actual tax paid, just gift tax return must be filed.

There might not be any gift tax. It depends on how many other taxable gifts the donor (giver) has made. If any gift tax is due, it would be the responsibility of the donor, not the recipient. However, if the donor does not pay, in some circumstances, IRS can go after the recipient. Sometimes, a donor and recipient will agree that recipient will pay the tax. If, so example, the tax is 40% (highest rate), then it would be treated as a net gift. So the tax would be $285,714, and you would get to keep $714,286 (plus any income earned on the $285,714 between receipt of the gift and April 15 of next year, when the tax is due). Note that even if no tax is due, a gift tax return must be filed. Also note that the first $14,000 given to you during any year is excluded, which presumably would save you up to $5,600 off the amount shown above.

You would not owe any gift tax. Any gift to you is tax free to you. The person making the gift will have to file a gift tax return and pay any taxes due.

When a person makes a gift to another person, the GIVER is responsible for reporting and paying the gift tax - the form is Form 709 and it is due on April 15 of the year following the year the gift was made. After the Taxpayer Relief Act of 2012 there is a permanent exclusion amount of $5 Million that each person has. This is "indexed" for inflation so this year the actual amount of the exclusion is $5, 250,000. Unless the person who makes this gift has already (in his or her life) made gifts of more than this amount, there would be no gift tax payable. There would be a gift tax return due even if no tax was owing.

One of the biggest misunderstandings of the gift tax is that the tax is the responsibility of the one who gives the gift, not the one that receives it. The amount would be determined by when the person gives/gave the gift, and how many previous gift Dollars, the person has given.