The response to the tsunami appeal is unprecedented, with £50m donated by Britons and more coming in every hour.
But what will your donation buy, and is money really the best way of helping?
Plastic sheeting to shelter one of the five million families who have lost their home costs only £8, while £100 will buy a proper family tent.
The average donation has increased to £100
But Save The Children says that even 60p can save lives. It will buy 100 water purification tablets, which will provide a family with 100 litres of drinkable water, preventing disease.
As the real scale of the disaster became clear, aid agencies started getting inundated by phone calls from members of the public offering money and help.
"We've had children coming into our high street shops and giving us their pocket money and pensioners giving us their pension," Pippa Ranger, a spokesperson for Save the Children, told the BBC News website.
What does your money buy?
75p: 10-litre jerry can for collecting and storing water
£5: full kitchen set for a displaced family
£15: clothes and shoes for a child who has lost everything
£35: enough food for a family for a week
£100: zinc sheeting and timber to rebuild two family homes
£400: a hand-held satellite phone for emergency teams to use
£1,750: a generator to provide electricity to an emergency camp
Source: Save The Children
She said: "Initially, the average donation was about £20 per person, but now that has gone up to £100 per person.
"Cheques we are getting in the post range from £100-£300, so that's a phenomenal response from the public."
'Worst ever disaster'
People involved in the massive fundraising operation believe the festive season has encouraged people to donate more generously.
A spokesperson for the Disasters Emergency Committee told BBC News: "Many people have been moved by the human tragedy which is unfolding on our screens.
"It really has been one of the worst disasters that the world has ever witnessed, and it's come at a time when many people have been on holiday.
"They are responding to the images they are seeing."
Donors come from all social backgrounds and donate according to their possibilities - but everybody does so with generosity described by charities as "unprecedented".
"One man called on behalf of his church to take a donation on Sunday to buy a boat and help a community that's been affected," said the spokesperson.
"One telephone bureau had received nine pledges of £5,000 each within a day," she added.
'Money is better'
Many people felt they should be doing more - possibly by travelling to the affected areas to work as volunteers.
But both the DEC and individual aid agencies are encouraging people to help through cash donations which, they say, is by far the most effective way of lending a hand.
"The Red Cross as an agency is asking for cash donations," said a spokesman for the British Red Cross.
Money is more essential than volunteers, charities agree
"If people in the UK want to know how they can help volunteer, we would ask them to contact their local branch by looking it up in the phone book or on our website," he added.
"People who are already there should make themselves known to the nearest agency providing assistance - it would obviously be a local decision whether or not they would take them on," he said.
Some charities, such as Save The Children, are looking for volunteers but say they must have previous humanitarian experience.
Merlin, a UK-based international humanitarian organisation, would like to hear from medical volunteers, while Red R - another relief organisation - is looking for engineers.
Members of the public have also contacted charities offering to adopt one of the thousands of children who have lost their parents.
But experts believe the best place for them to recover are in their communities.
Ms Ranger said: "In terms of the Save the Children perspective and also on behalf of the DEC, we would advise that children are best off staying in their communities and in their countries.
"That's the best place for them to recover and get the right support from people who speak their language.
"The best thing to do, again, is to donate money."
The DEC also suggests people contact agencies which run sponsorship programmes, such as World Vision and Action Aid to sponsor a child in one of the affected areas.