Government pensions will jump at least 4 percent next March. That is when the next catch up-with-inflation raise is due U.S. civilian and military retirees, including more than 100,000 here.

If inflation continues at its current level, federal-military pension increases in 1980 will exceed the record 10.8 percent jump they registered this year.

By law federal annuities are pegged to living costs as measured by the Consumer Price Index. Since beling linked to the CPI, a growing number of federal retirees have actually begun to receive pensions that are higher than their gross federal salaries when they used to work for Uncle Sam. That is little consolation, however, since inflation has devalued the worth of each increase they get.

Retired federal, postal, military and D.C. personnel get inflation adjustments every six months. Last March they received a 3.9 percent. During the same period white-collar federal workers received a flat 7 percent pay raise while executives got 5.5 percent.

The actual amount of the March annuity adjustment will almost certainly be high if inflation continues to climb over the next few months. Even if living costs were to drop, however, retiress are guaranteed a minimum of 4 percent in March payable in checks they will receive in April.