President Reagan's budget officially goes to Congress tomorrow. It includes a number of belt-tightening and "reform" proposals that would have a major impact on everybody who has ever worked for Uncle Sam, works for him now, or plans to in the future.

Washington's giant federal-military complex includes 402,000 federal workers and military personnel, plus 100,000 retirees.

There is little for them to cheer about in this budget. For example:

* The president asks Congress to support a pay freeze this year for federal white-collar and blue-collar workers, and the military. Civil servants would continue to get (in-grade) raises but they would be based on merit, rather than longevity. There would be no general pay raise this October.

* Federal and military retirees will get the cost-of-living adjustment (COLA) that goes into effect this April. It will show up in their May checks. The raise will be 3.9 percent for retirees who are 62 and older, and also for survivor annuitants and persons retired on disabilty. Retirees who are under 62 will get a 3.3 percent raise.

But the budget calls for a federal pension freeze for 1984. Under the plan, retirees would have to wait until mid-1985 for their next COLA.

Perhaps the most controversial item for government employes in the budget is the proposed change in federal retirement rules.

The retirement program is the crown jewel of the civil service.

President Reagan and his advisers believe it is overly generous, compared to most private pension plans. And he wants to make some changes in the U.S. system:

* The budget would require employes to work until age 65 to get full benefits.

Workers who retire before that age would take a 5 percent reduction in annuity for each year they are under 65.

Currently, employes can retire at age 55 with 30 years' service and get an annuity equal to 56.25 percent of their highest three year average salary.

The rules change would not apply to workers who are 55 or older at the time of enactment.

They could retire under current rules and not be subject to the 5 percent penalty.

* Employe contributions to the civil service retirement fund would be raised.

Workers now put in 7 percent of their gross salary.

Starting next year, all employes would be required to contribute 9 percent of their salary.

The contribution rate would be raised to 11 percent starting in 1985.

* The formula now used to compute annuities would be tightened. At present, benefits are determined by length of service and are based on an employe's highest three-year salary average.

That is called the High-3 formula.

The president is expected to propose a return to a system used years ago that bases annuities on the highest five-year salary average. That change would be phased in, officials say.

Is it going to happen? Nobody knows!

Congress would have to approve most or all of the proposed changes (and there may be some surprises in the budget).

It could approve them all, or kill them all. Or it could modify the proposals.

RIF Changes: The Office of Management and Budget is taking another look at its proposed changes in reduction-in-force rules.

OPM wants to give more layoff protection to employes based on their performance appraisal ratings, and to deemphasize seniority.

Last Monday, Republican legislators from the Washington area called on OMB to kill the proposed RIF changes.

OMB advised Rep. Frank Wolf (R-Va.) that it would extend its normal 10-day review period on proposed rule changes.

Despite the GOP opposition, OPM Director Donald Devine is fighting to keep the RIF rule changes intact.