system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is the Windows Explorer so bad in calculating time?

Again I am copying files and Windows Explorer estimates that it will take roughly 1 hour although it is copying with a stable speed. The copying took 10 minutes which I could easily calculate using simple math.
gpt
In the beginning of a file transfer, you're not really sure what speed you're going to get. As a result, the opening estimate is usually terribly wrong.

As you get more information on the actual average speed of the transfer, it'll make a better prediction. However, since hard drives may not have linear spaces open, the speed can fluctuate quite widely across the entire write.