Bandwidth & Download Time Calculator
Calculate download/upload time and required bandwidth for a file of a given size at a given connection speed.
Inputs
Estimated time
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In seconds
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In minutes
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Throughput
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With ~30% overhead
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About Bandwidth & Download Time Calculator
Why downloads feel slower
TCP overhead, packet loss, server-side limits, and your local Wi-Fi all reduce real-world throughput. A 100 Mbps connection often delivers 60-80 Mbps in practice.
Bits vs bytes
Bandwidth is measured in bits per second (Mbps). File sizes are in bytes (MB). 1 byte = 8 bits. So 100 Mbps = 12.5 MB/s peak.
Streaming bandwidth
SD video: 1-3 Mbps. HD: 5-8 Mbps. 4K: 15-25 Mbps. Add 30% overhead. A family of 4 streaming HD simultaneously can max out a 25 Mbps line.