In the most comprehensive survey of the wealth of Americans to date, the Census Bureau reported yesterday that the net worth of the typical white American household in 1984 was 12 times as great as the figure for the typical black household and 8 times as great as the typical net worth of Hispanics.

Overall, the bureau found that the median net worth of the nation's 86.8 million households in 1984 was $32,667. But breaking down the figures by race, the bureau found huge disparities among groups of Americans. The median net household worth for white households was $39,135; for black households, $3,397; and for Hispanic households, $4,913. Nearly one-third of all black households and one-quarter of Hispanics had no net assets or were in debt while fewer than one in 10 whites had no assets or were in debt.

The study found that 11 percent of all Americans -- or over 9 million households -- have no net assets at all, or are in debt, and that another 21 percent of households hold assets worth less than $10,000.

In addition, the survey showed that 12 percent of American households held 38 percent of all personal wealth in the nation.

The findings emerged from a new census survey using a sample of 20,900 households, the most ever used for an assessment of assets. The wealth figures reveal much greater disparities in the economic well-being of blacks, whites and Hispanics than do annual income figures, which until now have been the only available measure of economic status. While white annual income is less than twice that of blacks and Hispanics, the 12-to-l white/black wealth ratio and 8-to-1 white/Hispanic wealth ratio indicate that whites have reserves of assets far beyond those of blacks and Hispanics.

The huge difference between the median net worth of white and black households is the result partly of the large number -- nearly half -- of black households headed by women without a husband present and partly of low black income over generations, which has retarded the accumulation of wealth, said Gordon Green, assistant chief of the bureau's population division.

Net worth was derived by totalling the value of reported assets, such as homes, bank accounts, stocks and bonds, then deducting total liabilities, such as mortgages, loans and sums owed. A household can consist of a single person, a family or several unrelated persons. The median is the halfway point between the top and bottom; half the households have more, half less.

About two-fifths of net worth was in the form of equity in homes, a sixth in the form of savings accounts, certificates of deposit and other interest-bearing accounts.

Gaps between racial groups were not the only disparities among households masked by the overall $32,667 figure.

The bureau also found major differences among households according to age. Households headed by older people had a huge margin over younger ones, reflecting the fact they had accumulated nest eggs over many years and often owned homes whose mortgages had been paid.

By age, the lowest median net worth was among households headed by a person under 35, only $5,764; whereas the highest was among households headed by a person between the ages of 55 and 64, with a median of $73,664. People 65 and over had the second highest median net worth, $60,266. Green said that the oldest people owned less than those in the 55-to-64 age category because once retired, people often live on fixed incomes and tend to "spend down" their wealth to make ends meet.

The bureau found that the households with the highest median net worth are, for the most part, those with the highest annual income. The survey's highest income category -- households with $4,000 or more in income each month -- showed a median net worth of $123,474. These households, which constituted only 12 percent of all households, held 38 percent of the nation's total net wealth. On the other hand, the 26 percent of households that made up the lowest income group -- those earning less than $900 a month -- held less than 10 percent of the total net wealth.

Looking further at the extremes, the survey found that 16.9 percent of white households had net worth from $100,000 to $249,999, 4.4 percent had from $250,000 to $499,999, and 2.1 percent had $500,000 net household worth or more.

By contrast, the percentages among blacks for these three wealth categories were 3.3 percent, 0.5 percent and 0.1 percent; and among Hispanics, 5.1 percent, 2.1 percent and 1 percent.

The survey found that households headed by married couples had by far the highest median net worth of any type of household structure, $50,116, while households headed by a female, whether living alone or with others such as children, were at $13,885. Those headed by a man without a wife present were even lower, at $9,883. Married couple households were highest because many of them include two breadwinners, permitting accumulation of assets. Noncouple female-headed households had more assets than similar male-headed ones because they included large numbers of elderly widows who inherited considerable assets when their husbands died.

Households headed by college graduates had far higher accumulations of wealth than those less well-educated. Their median net worth was $60,417, compared to $31,892 for high school graduates, and $23,447 for those who had completed less than 12 years of school.

Officials said that the net worth figures were somewhat understated because the survey excluded several types of assets too difficult to estimate on a household basis.