You can leave up to 5 million dollar worth of property to your heirs without estate tax or gift tax.
It doesn't matter whether this 5 million dolloars worth of property is given during your life (gift), or after your death (inheritance).
Let's say if your gift to your child this time worth 1 million dollars, after your death, only the first 4 million of your estate is tax-free, instead of the usual 5 million