The calculated distance (air line) between Konstancin-Jeziorna and Białystok is approximately 112 miles respectively 180 kilometers.
By car or train, the actual journey to Białystok is certainly longer, as only the direct route (as the crow flies) between Konstancin-Jeziorna and Białystok has been calculated here.
Air line (approximately)
180 kilometers
97 nautical miles