Western industrialized nations yesterday hailed the price cut by the Organization of Petroleum Exporting Countries as a major boost for economic growth, and the cartel's members calculated how many billions of dollars they would lose from the unprecedented reduction.

The Soviet Union, while accusing the U.S. government and multinational oil companies of bludgeoning OPEC into lowering prices, reduced its own price by $1.25 a barrel, the third cut this year.

The Soviet action was not expected to have a serious market effect. A large reduction by Britain, however, could threaten the fragile agreement.

The strength of this year's expected world economic recovery and the degree to which OPEC members respect their new output ceilings will determine whether the cartel succeeds in avoiding a second price cut later this year, according to U.S. government and oil industry sources. Another factor is whether oil companies resume buying on the assumption that prices have bottomed out.

The sources stressed that Saudi Arabia--named by OPEC as the "swing producer" responsible for adjusting its output to maintain the new price--will have to accept extremely low levels of production for the next few months to stabilize the market.

"The agreement looks to me more like a holding action to prevent an immediate crisis than a permanent solution," Walter J. Levy, a prominent New York-based oil specialist, said.

OPEC's 13 members lowered the cartel's official price about 15 percent Monday, from $34 a barrel to $29, and established a set of production quotas to prop it up. The accord was designed to prevent open price war in the current oil glut.

Japan's Economic Planning Agency estimated that the price reduction would raise the nation's economic growth by .35 percent this year and nearly 1 percent in 1984, while reducing Japan's import bill by $6.7 billion, Agence France-Presse reported.

West Germany's Economic Ministry said that the price cut would spur growth and provide relief for many Third World countries burdened by high foreign debts and oil bills. Some U.S. officials estimate that a 15 percent drop in oil prices this year would increase the gross national product in this country by .5 percent.

On the other side of the market, the price cut alone could cost the OPEC countries about $20 billion in lost income in the first year, according to some estimates.

Venezuelan officials were quoted as estimating that oil income could drop by up to $5 billion this year, more than 40 percent, because of the price cut and a production cutback under the accord.

Indonesia, the OPEC country with the lowest per capita income, was expected to suffer particularly. The government finances 70 percent of its budget with oil revenues, which are expected to drop by more than $1.2 billion this year.

The Soviet news agency Tass, without mentioning its own price cut, accused Washington of "artificially kindling national, political and religious strife among the petroleum exporting countries," the Associated Press reported.

The OPEC member considered most likely to undercut the agreement is Iran. It refused to endorse the pricing part of the agreement and may be reluctant to honor its production ceiling of 2.4 million barrels a day, which would require an output cut.

Until world oil demand revives substantially, Saudi Arabia will bear the brunt of keeping down production to prop up prices. At current demand levels, the Saudis will be held to less than 3 million barrels a day, assuming other OPEC members respect their quotas. During the first half of 1982, the Saudis' average production was 7.2 million.