The report by the Interdisciplinary Journal of Research on Religion says the figure includes the value of services religious organisations produce and the impact religion has had on several top American businesses.
The authors concluded: "The faith sector is undoubtedly a significant component of the overall American economy, impacting and involving the lives of the majority of the U.S. population."
In total, 236 religious bodies and denominations participated, including 217 Christian denominations, Muslims, four Hindu groupings, three Jewish groupings and three Buddhist groupings.
The research, which encompassed 345,000 congregations across the United States and 150 million religious followers, also gave an higher estimate of $4.8 trillion which reflected the legacy of things including the Protestant Work Ethic.
Authors acknowledged the study does not account for the value of financial or physical assets held by religious groups or the negative impact caused by some religious communities, including "the abuse of children by some clergy, cases of fraud, and the possibility of being recruitment sites for violent extremism."
They added: "Religion is a highly significant sector of the American economy. Religion provides purpose-driven institutional and economic contributions to health, education, social cohesion, social services, media, food and business itself.
"Perhaps most significantly, religion helps set Americans free to do good by harnessing the power of millions of volunteers from nearly 345,000 diverse congregations present in every corner of the country's urban and rural landscape."