The calculated distance (air line) between Dunaharaszti and Kecskemét is approximately 42 miles respectively 67 kilometers.
By car or train, the actual journey to Kecskemét is certainly longer, as only the direct route (as the crow flies) between Dunaharaszti and Kecskemét has been calculated here.
Air line (approximately)
67 kilometers
36 nautical miles