The calculated distance (air line) between Kalsdorf bei Graz and Sankt Pölten is approximately 86 miles respectively 138 kilometers.
By car or train, the actual journey to Sankt Pölten is certainly longer, as only the direct route (as the crow flies) between Kalsdorf bei Graz and Sankt Pölten has been calculated here.
Air line (approximately)
138 kilometers
74 nautical miles