The calculated distance (air line) between Kyaikto and Nay Pyi Taw is approximately 178 miles respectively 286 kilometers.
By car or train, the actual journey to Nay Pyi Taw is certainly longer, as only the direct route (as the crow flies) between Kyaikto and Nay Pyi Taw has been calculated here.
Air line (approximately)
286 kilometers
155 nautical miles