How Much Does Total Government Spending Take Up?

The federal government is about 25% of GDP, leaving state and local to take up the rest.

usgovermentspending.com:

In 2011 the governments in the United States are expected to spend about 41 percent of Gross Domestic Product. Most of the money goes for health care, education, pensions, and welfare programs. Health care spending is split mainly between federal and state governments; education spending is mainly spent by local governments; pension spending is primarily the federal government’s Social Security program.