American taxpayers this week begin receiving the biggest dollar-volume tax cut in the nation's history, a $29.9 billion transfer from the government back to consumers that is being counted on to revive a battered economy.

The 10 percent, across-the-board cut for individuals, effective July 1, is part of a $749 billion, multiyear tax-cut program for business and individuals enacted last year by Congress--the core of the Reagan economic program.

Also this week, the nation's 36 million Social Security recipients will receive a 7.4 percent benefit increase, the customary biannual inflation adjustment. And more than 4 million aged, blind or disabled poor people will get a comparable percentage increase in their benefits.

For most workers, however, the individual cut is more than offset by this year's increases in employes' Social Security contributions and the shift of taxpayers into higher tax brackets because of inflation.

A married industrial worker with two children who is making $365 a week will get an extra $2.21 a week as the result of the July 1 cut.

For a clerk making $154 a week, take-home pay will grow by 62 cents.

And for an office manager making $595 a week, the weekly tax bite will drop by $9.91.

For each one of these workers, overall payments to the federal government in 1982 will be larger, not smaller, according to the Treasury. Raises that keep pace with inflation will push them into higher tax brackets, the value of personal exemptions and the standard deduction will decline in proportion to total wages, and hikes in the Social Security levy already have become law. Together, these will more than eat up the tax break for all middle-income and lower-income taxpayers.

The only people getting a real break in what they pay the federal government will be the very wealthy, generally those making at least $100,000 or more a year. For those making in excess of $200,000 a year, for example, the rate reductions constitute a real tax cut in 1982.

The very affluent are the major beneficiaries of the rate reduction on unearned income--interest and dividend payments--from 70 to 50 percent. That reduction went into effect on the first of this year. In addition, they are the largest beneficiaries in the capital gains rate reduction from 28 to 20 percent, retroactive to June 10, 1981.

This group will have a net tax reduction in 1982 averaging just over $18,000, despite higher Social Security and bracket-creep-induced hikes.

If this were to be translated into weekly withholding reductions starting July 1, it would mean an average tax reduction of about $690 a week for those making $200,000 or more.

The 10 percent reduction going into effect today is the middle stage of three rate reductions mandated in the 1981 law. The first, a 5 percent reduction, began on Oct. 1, 1981, and the third, a 10 percent reduction, will start on July 1, 1983.

Overall, these individual rate cuts are by far the most expensive part of the legislation, costing $25.8 billion this fiscal year, $65.7 billion the next, and rising to $143.8 billion in 1986.

The consequences of these cuts for individuals making less than $50,000 who depend on salary income are not, however, momentous, particularly when compared to some of the other provisions in the 1981 law.

Withholding on the salary of a hypothetical $615-a-week engineer at General Electric will drop by $10.67, from $107.50 to $96.83. For the engineer's corporate employer, GE, the corporate tax leasing provisions in the legislation were the most important reason that the firm's income taxes fell from $331 million in 1980 to a net refund of $100 million in 1981.

The fact that the majority of taxpayers will not get a real reduction in 1982 was documented most recently by the Treasury. According to its calculations, a family of four earning $25,000 in 1982--about the median--will get a tax "cut" of $305 for the whole year. At the same time, however, inflation and bracket creep should result in increased taxes of $302, leaving a net tax cut of $3 for the entire year. When the Social Security tax hike of $142 is added to the equation, the result is a net tax increase of $139.

Some House Democrats, including Ways and Means Committee Chairman Daniel Rostenkowski (D-Ill.), have suggested killing the third year of the individual rate cuts, the 10 percent reduction to go into effect on July 1, 1983.

Such an action, however, would have the effect of taking away far more tax benefits from middle-income and lower-income taxpayers than from the very rich, who benefitted more from the reductions on unearned income and other provisions.

A study by the Joint Committee on Taxation, for example, showed that, for all income classes below $200,000 a year, repeal of the third year of the tax cut would mean the loss of between 35 and 37 percent of the total rate reduction in the 1981 legislation. For those making more than $200,000, however, elimination of the third year would mean the loss of only 13.4 percent of their tax breaks. As a result, Democrats are backing off from a drive for repeal of the third year.