The federal gift tax is a tax by the government that applies to either assets left by a decedent at their death or assets given by an individual during their lifetime. In essence, whether you give your assets away while you are still living, or give them away when you die, they are subject to a tax. Gift tax applies to lifetime gifts; estate tax applies to assets left at death. Read on to learn about the federal estate and gift tax and how it may affect your estate.