Bank settlement date finder

The value date follows the settlement system's calendar, not the countries of the payer and payee: a euro payment settles when T2 is open, a US wire when Fedwire is. The national bank holidays of the offices involved matter for staffing, not for the value date. Bundled calendars are offline rule sets matching the published GOV.UK lists, the Federal Reserve schedule, and the ECB T2 closing days. One-off ad hoc holidays are not in any rule set, so add them as extra closures; on the US calendar a holiday falling on a Saturday keeps the prior Friday open, and one falling on a Sunday moves to the Monday. This is date arithmetic, not payment advice, and it does not read your bank's cut-off times.