A House subcommittee has estimated that President Reagan's decision to close down the federal government last November rather than sign an emergency spending bill wasted more than $85 million worth of the federal bureaucracy's time.

The staff of the House Post Office and Civil Service subcommittee on civil service surveyed 65 federal agencies in its review, scheduled to be released this week, of the Nov. 23 shutdown.

The staff arrived at its $85 million figure by first determining that 84 percent of the 1.05 million federal work force was declared "nonessential" employes that day. (The subcommittee excluded the Defense Department, Postal Service and Tennessee Valley Authority.)

Nonessential employes either were sent home, or, if still at work, were only supposed to be doing work related to shutting down the government. Since everyone got paid, whether they worked or not, the subcommittee calculated that 84 percent of the $102 million payroll for those agencies was wasted, or in its words, "must be considered direct shutdown costs."

The subcommittee report acknowledges that some nonessential workers may have performed their normal jobs, but it says "the subcommittee has to assume that nonessential employes were abiding by the law and therefore spent the day shutting down the government."

"We believe the final cost will be even higher than $85 million," said Andrew Feinstein, who compiled the report. The subcommittee still is trying to determine how much it cost the government for "essential" workers to issue furlough notices and how much time was wasted the day after the shutdown "starting up the government again," said Feinstein.

"From the beginning we have said that there is no precise way to determine what the shutdown cost," said Edwin Dale, a spokesman for the Office of Management and Budget, when asked about the subcommittee's report. "We have no comment."

Three weeks after the shutdown, the General Accounting Office prepared the only other report about its cost. Based on what it called "fragmented responses" from 25 agencies, it said closing the government for one day cost $8.2 million, based on the salaries of employes sent home and reports of costs attributable to shutting down the government.

Reagan ordered federal agencies to begin shutting down after he vetoed a $428 billion emergency spending bill that was $2.8 billion higher than he wanted. Reagan admitted his action would cause a "temporary hardship," but, he said, "continuing the past budget-busting policies of big spending and big deficits poses a far greater threat to all Americans."

The subcommittee's report found that federal agencies reacted differently to Reagan's order. Only 24 of the 65 agencies surveyed actually sent people home, the subcommittee said. Among the larger federal agencies, the General Services Administration sent home the highest percentage of employes, 72.8 percent. Overall, the subcommittee said, 126,921 federal workers were sent home by the agencies surveyed.

The Education Department reported the smallest percentage of essential employes: only two of its 6,263 employes were deemed essential, according to the report.

There was some confusion about who was sent home. The Health and Human Services Department told the subcommittee staff that it didn't furlough any of its 149,169 employes, but Washington Post reporters interviewed HHS workers outside the agency's headquarters that day who said they had been sent home.

The federal shutdown ended the day it began, after Congress passed and Reagan signed a continuing resolution to keep the government running. That resolution expires this month, but 10 of the 13 regular funding bills for federal agencies have been passed, so neither the administration nor Congress expects another shutdown, officials said.