Charity Cinnamon Network found the value of time given through social action projects by questioning 2,110 local churches and faith organisations.
It found that the time given was worth over £200 million locally, and when put on a national scale this adds up to over £3 billion a year, supporting 48 million beneficiaries.
Cinnamon Network said the majority of the hours were going into work with families, debt advice, helping people back into work, food banks and helping the homeless.
The report also found paid staff and volunteers were working with women and men in equal numbers, disproving the stereotype most work is done with females and children.
Matt Bird, founder of Cinnamon Network said: "The Audit findings were extremely revealing and leave us in no doubt about the crucial role faith groups in the UK play in delivering key social action projects in their cities or towns.
"As Cinnamon Network our vision is to see local churches and other faith groups more empowered and encouraged to take up their place as they serve at the heart of their community.
"We also want to see their work externally recognised and properly resourced as part of the overall picture of provision in any given community."
The Cinnamon Network said if its local survey figures were reflected on a national scale it would mean there were 219,889 Social Action projects being helped by Christians and support for 47,823,751 people.
It added that every year volunteer Christians gave up a total of 288,397,160 hours.
The report will be launched at an event in Westminster's Emmanuel Centre this evening by the Archbishop of Canterbury Justin Welby.