WASHINGTON — The Obama administration said on Sunday that it had met its goal for improving HealthCare.gov so that the website now “will work smoothly for the vast majority of users.”

In effect, the administration gave itself a passing grade. Because of hundreds of software fixes and hardware upgrades in the past month, it said, the website — the main channel for people seeking to buy insurance under President Obama’s health care law — is now working more than 90 percent of the time, up from 40 percent during some weeks in October.

Jeffrey D. Zients, the Obama adviser leading the website repair effort, said consumers were having a much better experience now than in early October. Pages on the website load faster — in less than a second — compared with an average of eight seconds in late October, Mr. Zients said. “The site is now stable and operating at its intended capacity, with greatly improved performance,” he said.

In a “progress and performance report,” the administration summarized five weeks of frantic activity to repair the website and undo damage to Mr. Obama’s political standing.