WASHINGTON — The five-week federal government shutdown took a significant economic toll, costing the United States economy $11 billion, with nearly a quarter of that total permanently lost, the Congressional Budget Office said on Monday.

The figures are the first official projection of the economic effects of the longest federal shutdown in history, and they show that its cost was nearly double the $5.7 billion request by President Trump for a border wall that fueled the impasse. That is enough to reduce first-quarter growth by about 0.4 percentage points.

Much of that spending was simply delayed, and will flow back into the economy as workers get back pay. But the report makes clear that not all the economic damage will be undone and that the effects of the shutdown will linger. With the federal government funded for just three weeks and Mr. Trump threatening to shutter the government again if his demands for a wall are not met, many workers say they are planning to spend less of their income and increase rainy-day savings.

Kelly Spencer, a federal contractor at the Justice Department, was planning to buy her first home this spring, but as she returned to work on Monday, she said she was shelving those plans.