Regex Editor & Tester

This regular expression validates California Department of Transportation (Caltrans) Expenditure Authorization (EA) numbers. It accepts either a literal placeholder format of 'XX-XXXXXX' or a specific structured code. The structured code optionally begins with 'C', followed by a valid month (01-12), a hyphen, a digit from 0-4, four alphanumeric characters, and must end with a '1' or '4'. It is highly useful for government accounting systems and administrative data entry validation.