The calculated distance (air line) between Budapest XXI. kerület and Dunaújváros is approximately 33 miles respectively 53 kilometers.
By car or train, the actual journey to Dunaújváros is certainly longer, as only the direct route (as the crow flies) between Budapest XXI. kerület and Dunaújváros has been calculated here.
Air line (approximately)
53 kilometers
28 nautical miles