Download Time Calculator
Estimate how long it will take to download a file based on its size and your internet speed. Supports KB, MB, GB and TB with Kbps, Mbps and Gbps connections.
How it works
The Download Time Calculator estimates the time required to download a file based on two inputs: the size of the file and the speed of your internet connection. The result is the theoretical transfer time at full link speed, in plain human-readable units.
The formula
The calculation converts your file size to bytes and your speed to bytes per second, then divides one by the other:
time (s) = file size (bytes) ÷ (speed (Mbps) × 1,000,000 ÷ 8)
Because 1 byte = 8 bits, every megabit per second of bandwidth delivers 0.125 megabytes per second of throughput. A 100 Mbps connection can therefore transfer at most 12.5 MB/s.
Why real downloads are slower
The number you get is the theoretical minimum. Real-world download speeds are lower due to TCP/IP overhead, encryption (TLS), server bottlenecks, Wi-Fi quality and other factors. Expect around 70–90% of your advertised speed in good conditions, and much less on a busy network.
Examples
Common download times for a 1 GB file:
- 10 Mbps → about 13 minutes 39 seconds
- 50 Mbps → about 2 minutes 44 seconds
- 100 Mbps → about 1 minute 22 seconds
- 500 Mbps → about 16 seconds
- 1 Gbps (fiber) → about 8 seconds
Frequently asked questions
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