That all depends on your internet connection speed and the site you are downloading from.
Most ISPs give their connection speeds in kilobits (kb/s) per second. Most programs give the download speed in kilobytes (KB/s). To get from the second back to the first, multiply the second by 8 (8 bits to a byte). Or take your connection speed and divide it by 8 to get an idea of how quick you can theoretically download files.
The ISPs speed is the theoretical maximum, and you will never reach it. Internet trafic in general, the quality of your phone or cable line and many other things will affect the download speed.
If you let us know what kind of cennection you have, we might be able to give a better answer.
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