Pastors in the US have shared their thoughts on who should be classified as a 'regular' church attendee.

A new study by Lifeway Research found that three in five protestant pastors expected someone to attend church at least twice a month to be considered a "regular" churchgoer.

For only one in ten, the requirement was once a month.

"There has likely never been unanimity on what qualifies someone as a regular churchgoer," Scott McConnell, executive director of Lifeway Research said.

"But the question piqued our interest recently as we have heard church leaders speculating that churchgoers are attending less often and that their mind-set of who is a regular attendee may be changing."

Other pastors had higher standards for "regular" churchgoers, with 15 per cent setting the threshold three times a month while 13 per cent said weekly. This was the case primarily for pastors over 65 (22 per cent) who defined regular attendance as someone who goes to church weekly or more.

Denominationally, Pentecostal, Restorationist Movement and Baptist pastors are more likely to consider only those who attend weekly or more as a "regular" attendee in their congregation.

When asked which church activities someone must attend to be considered a regular attender, six in ten pastors said they looked at Sunday church services rather than other weekly activities.

Physically attending church services is also essential for pastors when defining regular churchgoers, especially for younger pastors. Those aged 18-44 said they base their churchgoer definition on attending church services in person (42 per cent).

The study also showed the view from the pews.

Churchgoers tend to place the threshold according to their own frequency with 86 per cent of those who attend once a month saying a "regular" churchgoer goes to church with the same regularity.

For those who attend weekly, 60 per cent said the threshold should be established at least once a week or more.

"The study of churchgoers only provides insights from those attending each month, but there seems to be a consensus among that group that a regular churchgoer should be involved in the life of a congregation more often than not," McConnell said. "Pastors' perceptions of a regular churchgoer often appear broader, while those in the pew lean closer to a weekly standard."