A game update says 48 GB. Your internet plan says 100 Mbps. Is that a coffee break or an overnight job?
The two numbers use different units, which is why the answer isn’t obvious. This download time calculator converts everything for you and gives a straight answer, along with the little bit of arithmetic behind it so you can do it in your head next time.
How to use the Download Time Calculator#
- Enter the file size. Pick KB, MB, GB or TB next to the number.
- Enter your speed. Pick Kbps, Mbps, Gbps or MB/s, depending on what your plan or speed test shows.
- Add a speed loss (optional). Leave it at 0 for the ideal time. Try 10 to see a more realistic one.
- Read the time. The result shows the time in days, hours, minutes and seconds.
The one formula you need#
A download takes the size of the file divided by the speed of the connection. The catch is that file sizes are counted in bytes and speeds in bits. There are 8 bits in a byte, so you multiply the size by 8 first.
Take a 5 GB file on a 100 Mbps connection. 5 GB is 5,000 MB, which is 40,000 megabits. Divide by 100 and you get 400 seconds, or 6 minutes 40 seconds. Add a 10 percent speed loss and it becomes 7 minutes 24 seconds.
Mbps and MB/s aren’t the same thing#
This causes more confusion than anything else. A capital B means bytes and a small b means bits. Your internet plan is sold in megabits per second (Mbps). Your download manager often shows megabytes per second (MB/s). To convert, divide by 8: 100 Mbps is at most 12.5 MB/s.
So if your 100 Mbps line is showing 11 MB/s in a download, it’s working exactly as it should.
Download times at a glance#
These are ideal times with no speed loss, using decimal units (1 GB is 1,000 MB):
| File size | 10 Mbps | 50 Mbps | 100 Mbps | 500 Mbps | 1 Gbps |
|---|---|---|---|---|---|
| 1 GB | 13 min 20 s | 2 min 40 s | 1 min 20 s | 16 s | 8 s |
| 5 GB | 1 h 6 min | 13 min 20 s | 6 min 40 s | 1 min 20 s | 40 s |
| 50 GB | 11 h 7 min | 2 h 13 min | 1 h 7 min | 13 min 20 s | 6 min 40 s |
Why real downloads are slower#
The calculator gives you a ceiling, and real downloads usually land a little under it. The speed on your plan is the speed to your router, not a guarantee from the server on the other end. Wi-Fi interference, other people on your network, a busy server, and the small amount of data used up by the connection itself all take a bite. Mobile data swings up and down with signal.
If you want a number closer to real life, set the speed loss to 10 or 15 percent. For a very important download, test your actual speed first and use that figure.
A note on KiB, MiB and “Kibps”#
Some tools use binary units, where a kibibit is 1,024 bits, instead of the decimal kilobit of 1,000 bits. The gap is about 2.4 percent at the kilo level and about 7.4 percent at the giga level. This calculator uses decimal units, which is what internet providers and storage makers advertise. If your operating system reports a file in GiB, the file is slightly bigger than the same number in GB.
Small things that help#
- Use a cable instead of Wi-Fi for big files.
- Pause other downloads, streams and cloud backups while you wait.
- Start large downloads before you leave for the night, when networks are usually quieter.
Bits, bytes and overheads#
A 4 GB film is 32,000 megabits. On a 50 Mbps line that takes 640 seconds, or 10 minutes 40 seconds, if the line delivers the full speed. A 25 percent loss, common on busy Wi-Fi, stretches that to 14 minutes 13 seconds. Mobile data, VPNs and download servers that limit speed all add to the time. Game and app stores often download in pieces and verify them afterwards, so the progress bar may not move evenly.
Frequently asked questions#
About 13 minutes and 20 seconds with no speed loss. At 100 Mbps the same file takes about 1 minute 20 seconds.
Divide by 8. A 100 Mbps connection can move at most 12.5 megabytes per second.
The calculator assumes the full advertised speed. Wi-Fi, server limits, network congestion and protocol overhead usually reduce it by 5 to 15 percent.
Multiply the file size in megabytes by 8, then divide by the speed in megabits per second. The answer is in seconds.
A gigabyte is 1,000 megabytes and a gibibyte is 1,024 mebibytes, so a GiB is about 7.4 percent larger. Internet speeds and this calculator use decimal units.
The server, your Wi-Fi, other devices on your network and your provider’s own congestion all reduce it. Test with a cable, pause other downloads and try again at a quieter time. Enter a speed loss in the calculator to reflect your own typical results.