Download / Upload Time Calculator
Estimate how long a file transfer will take based on file size and connection speed. Handles mixed units — file size in MB/GB/TB, speed in Mbps/Gbps/MB-per-second.
Limitations: Assumes a steady connection. Real transfer time varies with TCP window size, server throttling, WiFi congestion, upstream/downstream asymmetry, and protocol overhead. "Up to" ISP speeds are usually not sustained.
What to do next: Most ISPs quote Mbps (bits); file sizes are MB / GB (bytes). 1 byte = 8 bits, so a 100 Mbps link transfers about 12.5 MB per second — not 100. Add ~10–15% overhead for TCP/HTTP.