President Reagan's economic game plan for the nation calls for fewer federal workers, up to 5,000 layoffs over the next seven months, a 4.8 percent federal raise in October, and fewer cost-of-living adjustments for federal and military retirees in future.

The budget Reagan will send Congress next month goes well beyond the Carter pay "reform" plan that died in Congress last year. It would end salary-open matchups between government and hand-picked industrial firms.

It would broaden the data base used to suggest annual catch-up-with-industry raises for U.S. workers, and probably reduce future pay raises for most federal employes. Using the "total compensation" concept, it weighs the value of federal pay plus fringe benefits (often more generous than those in industry) against the compensation package for similar jobs in the private sector. And it would require the federal government to consider salaries and fringes paid state and local government workers, who typically get less for the same job than their U.S. counterparts.

The Reagan budget would link white collar government pay to home-town private industry rates. That means federal workers in Detroit and New York could get bigger raises in the future than their federal colleagues in San Antonio, Louisville and other cities where private pay is lower.

The biggest change, however, would set the federal "comparability" pay rate at 94 percent of the going rate for the same job in industry. This would be done, the budget will say, because federal workers have benefits -- tenure, pension portability and automatic longevity raises -- not generally available to private industry employes.

Other big changes Congress will be asked to approve include:

Eliminating one of the twice-yearly cost-of-living adjustments that federal and military retirees get each year. Under the plan, retirees would get a single annual COL raise. (Before the election, candidate Reagan rpomised federal-military retirees he would not change the COL system that gives them raises every March and September.)

Divorcing military personnel from the federal white-collar pay-fixing system. Under Reagan's proposal, military aides -- including the 60,000 here -- would get full raises eacy year to match nationwide private industry pay gains.

Overhauling the federal employes' compensation program, which pays benefits to permanently disabled workers. The Reagan plan would give them 80 percent of their gross pay but, for the first time, make that income subject to federal income taxes.

Lowering personnel ceilings for non-Defense agencies by 43,000 jobs below the level set by Carter for the fiscal year ending Sept. 30, and reducing another 40,000 jobs below the Carter estimates in non-Defense civilian job totals for FY 1982, which begins Oct. 1. A late 1980 federal hiring surge pushed job totals up 20,000 more than Carter had projected for early 1981. Cutbacks that would be required between now and September can be made largely through attrition. But as many as 5,000 workers may be RIF-ed (fired) to meet new job ceilings in selected agencies, if Congress okays the cuts.

Sending new job ceilings to federal agencies within three weeks, and allowing those below the ceilings to lift the hiring freeze.Those over the ceiling would have to keep the freeze on longer and resort to RIFs to meet new, lower job levels.

Defense job totals this year would increase 14,000 above the amount targeted in the Carter budget. They would go up another 20,000 jobs over the Carter budget in fiscal 1982.

The job cuts, and increases, are misleading in that they are not based on current totals. Nobody knows the current size of the federal work force, and today's total won't be known for months. Changes proposed by Reagan are based on projections from the Carter budget estimates. The non-Defense side of government would drop, overall, 83,000 jobs between now and the end of fiscal 1982 based on figures Carter projected. Defense would gain 34,000 jobs over the projections for fiscal 1981 and fiscal 1982 in the Carter budget.