The RJT Date Calc program assists Family Historians in calculating dates from any two of the three following elements:

• Birth Date
• Event Date
• Age at Event

Quite an old program, with a several useful features. Does quick calculations between dates.

See http://www.taubman.org.uk/family/wp/software/birth-date-calculator/ for more details.

Note this utility uses the old Windows Help, so if you need to get the Help to work on Windows Vista and above please see Help pages refuse to display.

Link: RJT Date Calculator