Digital storage · transfer time
Download time calculator.
Enter the file size and your connection speed to see how long the download takes, and the MB/s that implies.
Inputs
Time needed
Enter the numbers above.
How long will my download take?
Time is the size in bits divided by the speed in bits per second. A file in gigabytes is multiplied by 8 to get gigabits, and an internet speed in Mbps is already in bits. The tool converts both to bits first, so you can mix units such as a size in GiB with a speed in MB/s. The efficiency box scales the speed down to model overhead; 100 percent is the ideal best case and is the default because no single real-world percentage is sourced.
Worked example. 70 GB is 560,000,000,000 bits. At 300 Mbps that takes 1,866.7 seconds, or 31 minutes 7 seconds. If you only get 80 percent of the plan speed (240 Mbps) it takes 2,333.3 seconds, or 38 minutes 53 seconds. A 1 GiB file on a 1 Gbps link takes 8.59 seconds.
Frequently asked questions
How long does it take to download 1 GB at 100 Mbps?
1 GB is 8,000 megabits, so at 100 Mbps it takes 80 seconds in the ideal case.
How do I calculate download time?
Multiply the file size in bytes by 8 to get bits, then divide by the speed in bits per second.
Why does my real download take longer?
Plan speeds are maximums. Overhead, Wi-Fi, server limits, and drive write speed lower the rate. Lower the efficiency box to model that, or use a speed test result.
Does the unit of file size matter?
Yes. 1 GiB is about 7.4 percent bigger than 1 GB, which adds that much time. Pick the unit your system reports.
Sources
Checked
- NIST, "Prefixes for binary multiples", opened 15 October 2026. kibi, mebi, gibi, tebi are 2^10, 2^20, 2^30, 2^40; under SI mega means 1,000,000, so 1 MB = 10^6 bytes and 1 GB = 10^9 bytes
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Scope
Ideal-case arithmetic. Actual time depends on latency, congestion, server limits and storage speed, none of which are modelled here beyond the efficiency percentage you set.