Senate-House plans to eliminate the "minimum" Social Security benefit would reduce, but not wipe out, monthly payments to about 3 million people, including 122,000 retired federal and postal workers.

The proposals, cleared by the House Ways and Means and Senate Finance committees, would do away with the $122 floor on monthly Social Security payments. Neither plan would eliminate any earned benefit. What they would do is limit individuals to amounts they actually earned under Social Security.

Many retired federal workers -- and over half of the people now working for Uncle Sam -- are (or will be) entitled to some Social Security benefits because of service in private industry.

Many people who get the minimum $122 per month benefit actually are entitled to only $60 or $80 per month. If the Senate-House plans become law, as seems likely, the minimum would be scrapped, but people would get whatever benefit they earned.

The Senate proposal would affect persons already retired and drawing the minimum benefit. If you are not entitled to it, you would be cut back to whatever amount you earned as a benefit while under Social Security. That would save the government a lot of money, but it would also require Uncle Sam to assign thousands of employees (one estimate is 5,600 people for a full year) to figure out who is entitled to what.

The House plan would eliminate the minimum benefit effective Dec. 1, 1981. If you are getting the minimum now, or qualified for it before Dec. 1, you could keep it, Persons coming eligible after that date would get only the Social Security payment they are entitled to.

The minimum-benefit proposal is separate from the plan announced last week by the Reagan administration to eliminate "windfall" benefits (that is the word they use) to federal and postal retirees and others who work the minimum amount of time under Social Security and qualify for benefits that often exceed those of persons who work a lifetime under Social Security. The Reagan plan would take into account the size of the federal or public pension an individual was receiving in determining how much he could also get from Social Security.