The micro-giving website Ploink has pledged to suspend the fees it charges for a year, which it estimates will add £200 a month to the amount charities using the service will receive.
The site, which describes itself as an "online collection box", enables people to pledge to give to any charity registered with the site by dragging and dropping virtual coins into a ‘piggy bank’.
When the coins add up to 99p or more, the money can be donated using a debit card, credit card or a PayPal account.
Ploink said it hopes that waiving its fees, which are a flat rate of 10p plus 10 per cent of the remaining donation, will encourage more people to donate.
Previously, if someone donated £2, the charity would receive £1.71.
So far 450 UK charities, including BeatBullying, Kidney Research UK, Make-A-Wish Foundation UK, the Meningitis Trust and World Vision UK have registered with the site, which was launched in 2009. Charities and donors can register for free.
Marc Simpson, director of Ploink, said: "At a time when people are giving less and charities are feeling the squeeze, Ploink wants to help buck the trend by giving people a fun and flexible way to donate.
"I hope that by suspending our fees, more will be encouraged to give in the knowledge that every penny and pound will be going straight to the causes that need them most."