Estimate how long a file takes to download at a given connection speed.
Calculated instantly in your browser.
How do you calculate file download time?
Time = file size in bits ÷ speed in bits per second. Remember 1 byte = 8 bits, so a 100 Mbps line moves about 12.5 MB per second. For example, a 5 GB file on a 100 Mbps connection takes about 6 minutes 40 seconds. This is a best-case estimate; real transfers are slower due to overhead and congestion.
Understanding your result
This is a best-case estimate. Real transfers are slower because of protocol overhead, network congestion and disk speed.
Formula and method
Time = file size in bits ÷ speed in bits per second. Remember 1 byte = 8 bits, so a 100 Mbps line moves about 12.5 MB per second.
Worked example
A 5 GB file on a 100 Mbps connection takes about 6 minutes 40 seconds.
How to use this tool
- Enter the file size and its unit.
- Enter your connection speed and its unit.
- Press Calculate.
About the Download Time Calculator
The Download Time Calculator estimates how long a file takes to transfer at a given internet speed, correctly handling megabits versus megabytes.
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Frequently asked questions
Why is my download slower than this?
Advertised speeds are maximums. Overhead, shared bandwidth, server limits and Wi-Fi all reduce real-world throughput.