File Transfer Time/Speed Calculator

Use this calculator to estimate file upload, download or transfer speed.  Actual transfer speeds may be a bit slower than these times due to reasons described below.

File Size

Select File Size Units Bits Bytes Kilobytes Megabytes Gigabytes Terabytes Petabytes

Select Transfer Speed 56 Kbps 128 Kbps 256 Kbps 512 Kbps 768 Kbps 1.544 Mbps T1/DS1 2.048 Mbps E1 10 Mbps Thin Ethernet 44.736 Mbps T3/DS3 100 Mbps Fast Ethernet 155.52 Mbps OC-3 622.08 Mbps OC-12 1000 Mbps Gig E

Resulting time

Your actual transfer speeds will likely be a bit slower than the calculator shows.  Why?  Because on a normal Internet connection your transfer speed is decreased by: Variable speed quality influenced by latency and jitter. Physical signaling overhead (e.g. The advertised transfer speed of a T1 line is 1,536 Kbps however 192 Kbps is usually tied up in the T1 line signaling protocol so the best you'll ever get is 1,344 Kbps) Layer 4 transport and transmission protocol maintainence/overhead.  Amazingly, these below processes can eat up to 10% of your transfer speed. Handshaking negotiation procedures between you and the place you are transferring the file such as "slow start" described technically in RFC 2001. TCP overhead, error checking and sending of protocol headers (e.g. Each IPv4 header is 160 bits, each UDP header is 64 bits, etc. ) If you are not transferring files over the Internet (TCP/IP) then these things will impact you less.