The calculated distance (air line) between Saint-Macaire-en-Mauges and Nantes is approximately 27 miles respectively 44 kilometers.
By car or train, the actual journey to Nantes is certainly longer, as only the direct route (as the crow flies) between Saint-Macaire-en-Mauges and Nantes has been calculated here.
Air line (approximately)
44 kilometers
24 nautical miles