The calculated distance (air line) between Kelsterbach and Bad Homburg vor der Höhe is approximately 12 miles respectively 19 kilometers.
By car or train, the actual journey to Bad Homburg vor der Höhe is certainly longer, as only the direct route (as the crow flies) between Kelsterbach and Bad Homburg vor der Höhe has been calculated here.
Air line (approximately)
19 kilometers
11 nautical miles