Download time
Estimate file download time from size and connection speed.
How to use
Enter the file size and the connection speed to estimate how long a transfer takes at full speed. File sizes can be given in MB, GB or TB and speeds in Mbps, Gbps or MB/s; the result is shown in days, hours, minutes and seconds.
Speeds are quoted in bits per second and files are measured in bytes, so the calculation multiplies the size by eight before dividing: time = size in bytes × 8 ÷ speed in bits per second. That is the step most mental estimates skip, and why a 100 Mbps connection moves at most 12.5 megabytes per second.
Sizes and speeds use decimal units, as storage makers and internet providers do: 1 GB is 1,000,000,000 bytes and 1 Mbps is 1,000,000 bits per second. Your operating system may show the same file in binary units (GiB), which look about 7% smaller.
Treat the result as a floor rather than a promise. Protocol overhead, a slower server, shared Wi-Fi and other traffic on the line all add to it: a 100 Mbps connection realistically delivers 11–12 MB/s, not 12.5. Upload speeds on many home connections are much lower than download speeds, so check which one applies.
Example
10 GB at 500 Mbps2 minutes 40 seconds at the theoretical rate.700 MB at 20 Mbps4 minutes 40 seconds.50 GB at 100 Mbps1 hour 6 minutes 40 seconds.1 GB at 10 MB/s1 minute 40 seconds: 10 megabytes per second is 80 Mbps.
Frequently asked questions
Why is my download slower than this?
The estimate assumes the whole line is yours and the server can fill it. In practice the slowest link in the path sets the speed, and that is often the server or the Wi-Fi rather than the connection you pay for.
Is 100 Mbps the same as 100 MB/s?
No, and the difference is a factor of eight. 100 Mbps is 100 megabits per second, which is 12.5 megabytes per second at absolute best.
How do I find my real speed?
Run a speed test while nothing else is downloading, preferably on a cable rather than Wi-Fi, and enter the result here in Mbps.
Does it work for uploads too?
Yes, with your upload speed. On many connections it is a fraction of the download speed, so a backup or a large video can take far longer to send than to receive.