The Big Give hopes to match £3m of donations via its website between 7 to 11 December. The matched fund will match any donation up to £5,000 pound for pound.
Supporters can search for the charity of their choice via The Big Give website and make their donation go further by selecting the “double your donation” button.
Over 175 UK charities will benefit from the fundraising effort, including The Princes Trust, the WWF and Best Beginnings, a charity supported by England and Arsenal footballer Theo Walcott.
Walcott says The Big Give will help charities such as Best Beginnings reach their fundraising targets twice as fast.
The Big Give was set up in 2007 by Alec Reed CBE as a search engine for match funding initiatives to bridge relationships between donors and charities.
Reed says: “I believe The Big Give’s £6m Matching Challenge presents a fantastic opportunity for anyone giving to charities this Christmas to make their donation go even further.”