The calculated distance (air line) between Mainz and Hofheim am Taunus is approximately 11 miles respectively 17 kilometers.
By car or train, the actual journey to Hofheim am Taunus is certainly longer, as only the direct route (as the crow flies) between Mainz and Hofheim am Taunus has been calculated here.
Air line (approximately)
17 kilometers
9 nautical miles