The flight distance from St Louis Regional Airport (ALN) in Alton/St Louis, United States to Tribhuvan International Airport (KTM) in Kathmandu, Nepal is 12,595 kilometers (7,826 miles / 6,801 nautical miles). The estimated flight time for this route is approximately 16h, flying north at a heading of 4°.

This is an ultra-long-haul route, one of the longest in aviation. It requires wide-body aircraft with extended range capability such as the Airbus A350-900ULR or Boeing 777-200LR. Passengers should prepare for an extended flight with multiple meal services.

This is an international route connecting United States with Nepal. It is an intercontinental flight between North America and Asia. Travelers should check visa requirements, customs regulations, and any travel advisories before booking.

Time zone information: When it's 10:00 in Alton/St Louis, it's 20:45 in Kathmandu. With a 10.75-hour time difference, travelers should plan for significant jet lag. It typically takes one day per hour of time difference to fully adjust.

There is a significant elevation difference of 3,847 feet between the two airports. Tribhuvan International Airport sits higher than St Louis Regional Airport.

The return flight from Kathmandu (KTM) to Alton/St Louis (ALN) follows a heading of 356° (north). Actual flight times may vary depending on wind conditions, air traffic, and the specific aircraft used.

For more information about these airports, visit the St Louis Regional Airport (ALN) and Tribhuvan International Airport (KTM) detail pages, or use our flight duration calculator to compare other routes.