The calculated distance (air line) between Munich and Heidenheim an der Brenz is approximately 75 miles respectively 121 kilometers.
By car or train, the actual journey to Heidenheim an der Brenz is certainly longer, as only the direct route (as the crow flies) between Munich and Heidenheim an der Brenz has been calculated here.
Air line (approximately)
121 kilometers
65 nautical miles