Despite the RIF (reductions in force) scare running through government, and estimates of major job cutbacks from unions, congressional office and pundits, nobody in Washington, from President Reagan down to the greenest bureaucrat, has any idea how many civil servants will be booted out of government because of budget or program cuts. Nobody!

Some federal agencies have a pretty good idea of the number of "jobs" they must eliminate during the remainder of this fiscal year (it ends Sept. 30) and next year. But how many of those "job" cuts will translate into flesh-and-blood people is still up in the air.

There will be RIFs. No doubt about it. And the Washington area, with about 14 percent of the overall federal workforce, will be hit. But hard numbers, or even close estimates, are not to be had.

The number of people actually put out of work will depend on how many job agencies must cut, on how many of those jobs are filled or unfilled, and on the attrition rate. One of the first tests of that will come at the National Bureau of Standards. It is scheduled to announce RIFs involving about 200 jobs this week.

Many workers who get RIF notices across the government will not be fired. Depending on how the layoffs are run and the "competitive area" of RIFs, many senior workers whose jobs are to be abolished will be able to bump or displace less senior employes. In most cases the last hired wind up being the first fired. Again it depends on how agencies tailor their individual RIF programs.

In a move to encourage senior workers to retire, half a dozen agencies have asked the Office of Personnel Management to give them "early out" authority. In an eary-out employes with 20 years of service can retire early, on immediate (but reduced) pensions, as can workers at any age with 25 years service. But agencies cannot offer the option unless OPM okays it. Early-outs, by law, are supposed to be limited to departments and agencies that are facing major job cutbacks. Often they are limited to specific geographic areas, and sometimes to certain grade levels or occupations due to be hardest hit by RIFs.

Bear in mind that OPM has not yet ruled on the early-out applications. OPM has moved to tighten up early-out retirements, so the fact that a particular agency may have requested such authority doesn't mean anything unless and until OPM gives it the green light.

If agencies get the early-out authority (and more will request it as the RIF picture becomes clearer) and a lot of workers retire early, then fewer people will have to be laid off. If agencies don't convince OPM that they need the early-out authority, or if they offer it and relatively few people retire early, the RIFs will be deeper. Here are the agencies that have requested early-out authority:

Commerce Department, two requests for early-out authority. One to cover all headquarters workers of the Maritime Administration, the other to cover all employes (here and in the field) of the National Oceanic and Atmospheric Administration.

Interior Department, one early out request. It would cover all workers eligible in the Heritage Conservation and Recreation Service.

Interstate Commerce Commission has requested the early-out to cover all eligible employes here and in the field.

Environmental Protection Agency, two requests. One for all personnel at Environmental Protection Agency headquarters. The second for its western Region 10.

Labor Department (based on job estimates through fiscal 1982) wants the early-out authority to cover all employes nationwide.

The Office of Personnel Management has instructed agencies that are planning to RIF people to give them first crack to job openings elsewhere, and it has set up a task force to coordinate agency RIF and hiring programs. a