The congregation of Bath Abbey gave more than £200,000 of voluntary help to the city last year, according to a survey by the church.
The landmark church's worshippers contribute more than 28,000 hours of unpaid time a year.
Around two-thirds of this is within the abbey, but the other third is in the city community as a whole.
The survey - which used the Living Wage to calculate the value of the work - showed that its congregation put in 345 hours a week at the abbey alone, doing activities from welcoming visitors and stewarding concerts to running children's groups and supporting services.
Worshippers devote an average total of 195 hours a week to other local charities and organisations.
Activities include visiting the elderly, helping with educational workshops, staffing soup runs for homeless people, and acting as Mayor's Guides to show visitors around the city. One worshipper is even a lock keeper.
Nick Holland, who welcomes visitors to the abbey, said: "The abbey has always fascinated me and I enjoy meeting new people.
"I may welcome in excess of 1,000 visitors from every corner of the earth and every walk of life in the few hours of my shift, offering a fresh challenge every time. I enjoy being part of the abbey and have yet to meet a volunteer who doesn't have a smile on their face and a real willingness to give. Giving up a relatively short amount of time is a rewarding way in helping the workings of an iconic place of worship."
Abbey rector Prebendary Edward Mason, said: "We hear a lot of talk about the Big Society. Here we celebrate a big-hearted society, one which contributes hundreds of hours to the abbey as well as the wider city every week.
"We are extremely grateful to our volunteers, but also very proud of the contribution our congregation makes outside the abbey. It just goes to show how interlinked the abbey and the city are."
To find out about volunteering at the abbey, contact Dawn Farmer on 01225 303310 or email visits@bathabbey.org.
