Every retired person in America drawing federal, military or social security benefits-- including nearly half a million persons here -- will get a 3 1/2 percent boost in benefits starting in January based on cost--of--living data released yesterday by the Labor Department.

The same increase will go into effect the first of the year for all white-collar federal workers. There are more than 350,000 in the Washington-Baltimore area.

Nationwide, more than 1.4 million workers, and nearly 2 million federal retirees will get the raises.

White-collar federal workers got their last, 4 percent raise in January, when social security benefits went up 3 1/2 percent. The last increase for federal and military retirees was a 3.9 percent adjustment in April 1983.

The typical federal retiree gets about $12,000 a year in retirement benefits, according to the Office of Personnel Management. The average federal worker here earns $30,784 a year; the median federal salary (the same number of people above the line as below) in this area is $27,252, the Office of Personnel Management calculates.

That COLA adjustment announced yesterday will boost the federal employe-annuitant payout to more than $1 billion a month in the Washington area. Traditionally, federal pay and pension adjustments are followed by a round of price hikes in everything from parking lot fees to rents and groceries.

The COLA is based on the rise in national living costs, as measured in the Consumer Price Index, from the third quarter of 1983 to the third quarter of this year.

Unlike retiree increases, which are linked to the inflation rate, pay boosts for federal white-collar workers are largely a political decision made by the president and Congress.

President Reagan last August recommended the 3 1/2 percent increase in lieu of a recommended 18 percent adjustment. It was recommended by government pay experts, who said it should be made this month to keep civil service salaries on a par with the salaries for similar jobs in the private sector.

The annuity increases will go to all of the nearly 2 million federal retirees, from ex-presidents to one-time clerks, or their widows or widowers, regardless of age. Congress late this year dropped a provision from the law that would have based percentage increases on the age of the retiree.

The Washington area has one of the biggest concentrations of government retirees, but there are also sizable numbers in California (201,000), Florida (125,000), Texas (102,000), Pennsylvania, Ohio, Washington state, New Jersey, Massachusetts, Illinois, Alabama and Georgia.