The landing speed (often referred to as Vref) of a Boeing aircraft varies significantly based on the model and its weight (fuel remaining and cargo/passengers). For the popular Boeing 737-800, the landing speed is typically between 130 and 150 knots (approx. 240–280 km/h or 150–170 mph). Larger aircraft like the Boeing 777 or 747 may land slightly faster, often between 150 and 160 knots, due to their immense mass. Pilots calculate this speed based on the "Final Approach Speed," which is usually 1.3 times the stall speed in the landing configuration. As the plane touches down, it must be slow enough to stop within the runway length but fast enough to maintain lift. Factors like wind "gusts" can add a "wind additive" to these speeds for safety. Once the wheels hit the tarmac, the "ground speed" is immediately reduced through a combination of aerodynamic braking (flaps/spoilers), wheel brakes, and engine thrust reversers, bringing the massive machine to a taxiing speed in just a few thousand feet.