Estimated time of arrival

The estimated time of arrival or ETA is a measure of when a vehicle or aircraft in travel, cargo, or emergency services is expected to arrive at a certain place. One of the more common uses is in public transportation where the movements of trains, buses, airplanes and the like can be used to generate estimated times of arrival depending on either a static time table or through measurements on traffic intensity.

For example: a certain flight may have a calculated ETA based on the speed by which it has covered the distance traveled so far. The remaining distance is divided over the speed hitherto measured to get a rough estimate on arrival. This particular method does not take into account any unexpected events (such as new wind directions and the like) which may occur on the way to the site of arrival.

The ETA acronym is often used sloppily in situations where nothing that actually moves over a distance is arriving anywhere, such as the time estimated for a computer program to finish a certain calculation.