A formula (KOBOTOOLBOX) that works can be used to automatically determine age from a selected date. The date should be limited to 1924 to 2007 and the age range should be between 18 and 100. Thanks!

@gscart , seems like this is something what you are seeking for … [image] Validating date entry Form Building Adding this line should solve your issue: In the survey tab of your XLSForm: [image] Data entry screen as seen in Enketo: when a wrong entry is made [image] …