The calculated distance (air line) between Šempeter pri Gorici and Slovenj Gradec is approximately 80 miles respectively 128 kilometers.
By car or train, the actual journey to Slovenj Gradec is certainly longer, as only the direct route (as the crow flies) between Šempeter pri Gorici and Slovenj Gradec has been calculated here.
Air line (approximately)
128 kilometers
69 nautical miles