The calculated distance (air line) between Wielki Kack and Bydgoszcz is approximately 95 miles respectively 153 kilometers.
By car or train, the actual journey to Bydgoszcz is certainly longer, as only the direct route (as the crow flies) between Wielki Kack and Bydgoszcz has been calculated here.
Air line (approximately)
153 kilometers
82 nautical miles