They can choose to do so while checking balances or making withdrawals, although the choice and number of charities involved is up to individual ATM operators under proposals confirmed yesterday.
Royal Bank of Scotland (RBS) cash machines and those owned by independent operator Bank Machine will be first to put the scheme into action.
The initiative is being rolled out through the Link network, but the initial phase includes only the 12,000 machines owned by Bank Machine and RBS.
Screens will display the option as a separate option – and 550 charities have already applied to be involved.
HSBC has allowed its customers to make ATM donations since 2005.