The research, which reviewed the performance of 61 charity websites over the past financial year, shows that despite the success of a small number of high-profile charities such as Comic Relief, few organisations attract more than a handful of online donations.
"It is clear that there is as yet little sign of an e-philanthropy revolution in the UK," said Adrian Sargeant, professor of non-profit marketing at the University of the West of England, who wrote the report with Elaine Jay, also from the university. "In most cases a presence on the web is still a cost to UK charities."
As well as collating financial data about the performance of the websites, the researchers tested the sites from a user's perspective by trying to donate £10 to each charity that offers an online facility. In seven cases, an online donation could not be made.
"Charities would be well advised to check their online giving mechanisms regularly by actually giving a donation, as many of the problems we encountered came at the end of the process," said Sargeant.
A further 10 charities failed to send any kind of communication after the donation, and in other cases it took two months for the charity to communicate with the new donor.
The report also discovered that only three of the 61 sites prompted the donor to give a specific value, a common practice in direct mail campaigns.
And 88 per cent of charities use direct mail to develop relationships with online donors, even though they are known to prefer email.
To see the report visit www.charityfundraising.org.