Calculate
Method and assumptions
Seconds = file-size bits ÷ entered bits per second. One byte is eight bits. Decimal MB/GB and binary MiB/GiB are distinct. When enabled, effective rate = entered rate × your percentage; the unadjusted estimate remains visible.
Worked example
1 GB at 100 Mbps takes 80 seconds ideally. 1 GiB at the same rate takes about 85.8993 seconds. At an entered 80% effective throughput, 1 GB takes 100 seconds.
Limitations
This is not a speed test. Congestion, protocol overhead, server limits, Wi-Fi, and other traffic can change the actual time. No connection or file is tested or uploaded.
Frequently asked question
Are Mbps and MB/s the same?
No. Mbps measures millions of bits per second; MB/s measures millions of bytes per second, eight times as many bits.
References
NIST binary-prefix definitions. These are reference sources, not endorsements.