The calculated distance (air line) between Bagan Serai and Bukit Mertajam is approximately 25 miles respectively 40 kilometers.
By car or train, the actual journey to Bukit Mertajam is certainly longer, as only the direct route (as the crow flies) between Bagan Serai and Bukit Mertajam has been calculated here.
Air line (approximately)
40 kilometers
22 nautical miles