The SI measurement of speed and velocity. This is the number of meters travelled in one second of time. The accompanying acceleration unit is meters per second per second (m/s²).
Knots are a speed measurement that is nautical miles per hour. This unit is typically used in maritime and aviation. There have historically been different nautical miles used and, thus, different variations of knots. However, we have based our knots calculator on the international nautical mile which is commonly used thoughout the world today.