definition

Speed

Speed is the rate at which distance is traveled. It is a scalar quantity, so it does not include direction.

By AskToBot Editorial Team · Updated October 5, 2026

Speed is the rate at which distance is traveled. It is a scalar quantity, so it does not include direction.

Simple example

Traveling 100 m in 20 s gives an average speed of 5 m/s. Velocity also specifies direction.

Read units together with the number. A value without its unit can be ambiguous; a ratio such as a percentage also needs its reference whole.

Use the Speed Calculator to connect the concept to a worked calculation.

Find average speed from distance and elapsed time.

Estimate distance from average speed and travel time.

Energy is a physical quantity associated with the capacity to do work or transfer heat. The SI unit is the joule.

Estimate electrical energy in kilowatt-hours from watts and hours.

Divide total distance by total elapsed time.

For DC circuits, multiply voltage by current: P = V × I.

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