Velocity is measured as the rate of change of an object's position with respect to time, including both speed and direction. The most basic way to measure velocity is to use the formula:

velocity=displacementtime\text{velocity}=\frac{\text{displacement}}{\text{time}}velocity=timedisplacement​

where displacement is the straight-line distance between the starting and ending points with direction, and time is the duration of travel. For example, if an object travels 500 meters east in 180 seconds, the average velocity is 500180=2.78 m/s east\frac{500}{180}=2.78,\text{m/s east}180500​=2.78m/s east.

For objects accelerating or changing velocity, the final velocity can be calculated using:

v=u+atv=u+atv=u+at

where vvv is the final velocity, uuu the initial velocity, aaa the acceleration, and ttt the time elapsed. The average velocity when accelerating can be found by averaging the initial and final velocities.

Different methods exist to measure velocity depending on context, such as kinematic methods (tracking marked fluid volumes), dynamic methods (using probes or electromagnetic fields), and physical methods (such as hot-wire anemometers or laser Doppler anemometry) for fluids or gases.

In summary, velocity is measured by determining displacement over time for linear motion, and for changing speeds, by incorporating acceleration into calculations. Specialized instruments and methods apply for measuring velocity in fluids and other complex media.