GNW / Free calculator
Download Time Calculator
Enter a file size and connection speed. Compare an ideal transfer with a practical estimate using your chosen speed efficiency.
Enter your values and choose Calculate.
Estimates only. Values are calculated in your browser and are not sent or saved by this tool.
How download time is calculated
Time in seconds = file size in bytes × 8 ÷ connection speed in bits per second. We use decimal units: 1 GB = 1,000 MB, and 1 Mbps = 1,000,000 bits per second.
The practical estimate divides ideal time by your efficiency fraction. For example, 10 GB over 100 Mbps takes 13 minutes 20 seconds ideally, or 16 minutes 40 seconds at 80% efficiency.
Why actual speed changes
Wi-Fi conditions, server limits, other devices and protocol overhead can extend a transfer. Efficiency is your assumption, not a measured property of the connection. This tool does not run a speed test.