The calculated distance (air line) between Erfurt and Marburg an der Lahn is approximately 99 miles respectively 160 kilometers.
By car or train, the actual journey to Marburg an der Lahn is certainly longer, as only the direct route (as the crow flies) between Erfurt and Marburg an der Lahn has been calculated here.
Air line (approximately)
160 kilometers
86 nautical miles