Federal worker furloughs cost the government 6.6 million work days in last month's partial government shutdown.
That's according to the White House budget office.
Taxpayers will foot the $2 billion cost of providing back pay to the 850,000 workers sent home during all or part of the 16-day shutdown.
The Obama administration has already said the shutdown, and uncertainty over raising the government's borrowing cap, will curb economic growth in this quarter.
The budget office says closing national parks cost communities $500 million in lost spending by visitors.
And the IRS delayed $4 billion in tax refunds and will have to delay next year's filing season by up to two weeks.