Double die pennies are among the most sought-after error coins in U.S. numismatics. A double die error occurs when the coin die receives a doubled impression during the hubbing process, leaving a visible doubling on the design elements of the struck coin. ErrorHunt uses AI to detect these errors from a photo.
Look for visible doubling on lettering, the date, or design elements. Under magnification, the doubling appears as a clear secondary image offset from the primary. Minor die deterioration doubling (DDD) is common and not valuable — ErrorHunt's AI is trained to distinguish between the two.
ErrorHunt is an AI-powered coin error detection platform designed for collectors, treasure hunters, and anyone curious about the value of their coins.