The federal government's one million clerks, scientists, lawyers and other white-collar civil servants would get a 5.5 percent raise next October -- their smallest pay increase in years -- under a sharply revised budget President Carter will send Congress later this month.

Carter's final budget also will propose a raise in excess of 9 percent for military personnel, who normally get the same raises as U.S. civilian workers.

Federal workers, whose pay raises each October are based on recommendations of the president, got a 9.1 percent increase last year. Carter budget aides had originally settled on a recommendation of 8.7 percent for government workers this October, and a 9.25 percent adjustment for the military.

The decision to trim that raise for white-collar workers was a last-minute attempt to cut some red ink from Carter's final budget recommendation. Each 1 percent increase in federal pay costs around $500 million, so the change would trim more than $1.5 billion from budget estimates for the fiscal year that begins Oct. 1.

Reducing the size of the federal raise will trim the budget deficit, and generally prove popular with Congress and the public. Lowering the targeted raise from 8.7 percent to 5.5 percent also will cut some ground out from under President-elect Ronald Reagan, who has promised to cut federal spending programs.

Keeping the military raise higher should also be politically popular and make it tougher for the handful of congressional backers of higher federal pay -- most of them Washington-area legislators -- to get more for government workers.

White-collar federal pay rates are supposed to be keyed to counterpart jobs in the private sector under a complicated and controversial "comparability" formula set by law. It requires the Bureau of Labor Statistics to measure selected firms in the United States (but excludes pay rates for 12 million state and local government employes) and come up with recommendations for U.S. government pay raises to be made in October.The president has the power to lower those proposed increases, though Congress can veto the lowered raise and allow the higher raise to take effect.

In recent years presidents have -- for economic and political reasons -- recommended October increases that were less than the comparability formula dictated. Last year, for example, federal workers were due increases in excess of 13 percent, but Carter lowered the amount of the raise to 9.1 percent.

Early last year Carter proposed a "reform" of the federal pay-fixing system that he said would give a more accurate comparison of federal and industrial pay rates. His plan, which was not acted on by Congress, would have linked federal white-collar wages to home-town rates for similar jobs, measure the value of federal fringe benefits against those in industry and also base federal pay rates on salaries paid state and local government workers. Federal unions objected to the plan, claiming it would have cost the typical federal civil servant $1,500 in raises over the next few years.

Reagan has not taken a stand on the pay "reform" package recommended by Carter. But it is a good bet that the Republican-dominated Senate and the new House will take a closer look at the reforms this year.

The budget proposals for white-collar federal workers do not have a direct effect on wages for the 600,000 postal workers or the government's half-million blue-collar (wage board) employes.

Postal salaries are set by negotiation between AFL-CIO unions -- representing 80 percent of the workforce -- and officials of the U.S. Postal Service. The current 3-year postal contract expires next July, and negotiations are due to begin in a couple of months on the next contract.

Raises for blue-collar federal workers supposedly are based on wage gains in home-town industry. But in practice Congress in recent years has "capped" blue-collar raises based on what white-collar civil servants get.