File Download Time Calculator Enter a file size in the box below to see how long it will take to download for each of the listed circuit speeds. File Size: KB (Kilobytes) MB (Megabytes) GB (Gigabytes) TB (Terabytes) PB (Petabytes) XB (Exabytes) Note: these calculations assume a "perfect" connection at the stated speed. Actual performance will vary due to retries, latency, transmission protocol requirements, and other concurrent traffic. Connection Capacity Time 33.6 K (Modem) 33,600 bps 56 K (Modem) 56,000 bps 64 K (DS-0) 64,000 bps 128 K (ISDN) 128,000 bps 256 K (DSL) 256,000 bps 640 K (DSL/Cable) 640,000 bps 768 K (DSL/Cable) 768,000 bps T1, DS-1 1.544 Mbps Comcast UP 25 Mbps T3, DS-3 44.736 Mbps OC-1 51.840 Mbps Comcast 75 75.000 Mbps 100 Base 100.00 Mbps OC-3 155.520 Mbps OC-12 662.080 Mbps 1 Gig 1 Gbps OC-48 2.488 Gbps OC-192 10 Gbps OC-768 40 Gbps OC-3072 (STM1024) 160 Gbps STM4096 640 Gbps