The official size of the federal civilian work force declined by 44,268 employes during President Reagan's first eight months in office, but the drop was not quite as much as Reagan had ordered.

In April the Office of Management and Budget told each executive branch agency how many employes it could have on Sept. 30, the last day of the fiscal year. The governmentwide total was 2,092,100. Preliminary figures from the Office of Personnel Management show that 2,143,388 employes were on the payroll, including about 25,000 who were exempt from the Reagan ceiling. (The numbers do not include the 663,100 employes of the U.S. Postal Service, who are included in the Data Base on this page).

Thus, government managers missed Reagan's slim-'n'-trim target by about 26,000.

Sixteen of the 29 largest federal agencies finished the year with more workers than expected; 13 of the 29 met the target. Two others--Justice and Housing and Urban Development--nudged close enough that they will meet their ceilings after employes exempt from the official count are subtracted.

Some agencies have grown since Reagan took control of the government in January. Not surprisingly, civilian employment at the Defense Department increased from 972,900 to 984,183, but the departments of State and Agriculture and the NRC also paid more people in September than in January.

The largest declines from January to September were at Treasury (which usually has a large number of seasonal employes in the early part of the year--the tax season), Transportation (which fired many air traffic controllers this summer) and Health and Human Services.