The calculated distance (air line) between Westgate on Sea and Southend-on-Sea is approximately 29 miles respectively 46 kilometers.
By car or train, the actual journey to Southend-on-Sea is certainly longer, as only the direct route (as the crow flies) between Westgate on Sea and Southend-on-Sea has been calculated here.
Air line (approximately)
46 kilometers
25 nautical miles