The calculated distance (air line) between Gau-Algesheim and Wiesbaden is approximately 14 miles respectively 22 kilometers.
By car or train, the actual journey to Wiesbaden is certainly longer, as only the direct route (as the crow flies) between Gau-Algesheim and Wiesbaden has been calculated here.
Air line (approximately)
22 kilometers
12 nautical miles