The calculated distance (air line) between Sungai Petani and Bukit Mertajam is approximately 20 miles respectively 32 kilometers.
By car or train, the actual journey to Bukit Mertajam is certainly longer, as only the direct route (as the crow flies) between Sungai Petani and Bukit Mertajam has been calculated here.
Air line (approximately)
32 kilometers
17 nautical miles