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