The calculated distance (air line) between Balassagyarmat and Kecskemét is approximately 83 miles respectively 133 kilometers.
By car or train, the actual journey to Kecskemét is certainly longer, as only the direct route (as the crow flies) between Balassagyarmat and Kecskemét has been calculated here.
Air line (approximately)
133 kilometers
72 nautical miles