Senate-House budget conferees have tentatively agreed to a compromise that would give white collar federal workers a 4 percent raise this October and limit government retirees to a 4 percent cost-of-living adjustment next March.

Although the numbers aren't big, the compromise would represent the best deal, under the circumstances, the 400,000 workers and retirees here could expect.

Most of the compromising on the federal pay-pension issue came from the Senate side. It originally voted to skip any 1982 federal pay raise, and to delay the next COL for retirees until March 1984 and then "cap" it at 4 percent.

The Republican budget approved by the House called for a 4 percent federal raise this year, and a full COL catch-up next March for retirees.

Federal union leaders and lobbyists performed yeoman service in winning the tentative 4 percent compromise. Normally, conferees split the difference.

The strong push for a 4 percent raise came from the House, which mustered strong--but losing--votes in early budget tests for a raise of either 7 percent or 5 percent. Post Office-Civil Service Committee Chairman Bill Ford (D-Mich.) pushed for the highest possible raise. Maryland Democrats Steny Hoyer, Mike Barnes and Roy Dyson lobbyied often-reluctant colleagues for the maximum amount.

Frank Wolf and Stan Parris of Virginia, and Marjorie Holt of Maryland worked GOP conferees to protect at least a 4 percent raise, and to keep the March 1983 raise for retirees on schedule.

If the tentative compromise holds up, the full Senate and House are expected to endorse the 4 percent amounts.

Four percent may not sound like much to some feds. But it is twice as much as most political realists expected, and the Senate wanted 0.0 percent.