The calculated distance (air line) between Décines-Charpieu and Clermont-Ferrand is approximately 90 miles respectively 145 kilometers.
By car or train, the actual journey to Clermont-Ferrand is certainly longer, as only the direct route (as the crow flies) between Décines-Charpieu and Clermont-Ferrand has been calculated here.
Air line (approximately)
145 kilometers
78 nautical miles