The calculated distance (air line) between Balatonboglár and Budapest XXI. kerület is approximately 81 miles respectively 130 kilometers.
By car or train, the actual journey to Budapest XXI. kerület is certainly longer, as only the direct route (as the crow flies) between Balatonboglár and Budapest XXI. kerület has been calculated here.
Air line (approximately)
130 kilometers
70 nautical miles