The calculated distance (air line) between Tápiószentmárton and Budapest III. kerület is approximately 36 miles respectively 57 kilometers.
By car or train, the actual journey to Budapest III. kerület is certainly longer, as only the direct route (as the crow flies) between Tápiószentmárton and Budapest III. kerület has been calculated here.
Air line (approximately)
57 kilometers
31 nautical miles