Note: MB = megabytes (8 Mb), GB = gigabytes, TB = terabytes.
Mbps / Gbps = megabits / gigabits per second (network speeds). MB/s / GB/s = megabytes / gigabytes per second (storage speeds, e.g. NVMe).
TCP/IP overhead, protocol headers, encryption, etc. typically reduce effective throughput to 70–90% of nominal link speed.
About this tool
A key source of confusion in transfer time calculations is the bit/byte distinction: network speeds are quoted in bits per second (Mbps, Gbps) while file sizes are in bytes. 1 byte = 8 bits, so a 1 Gbps link can transfer at most 125 MB/s of data. Protocol overhead from TCP/IP headers, TLS encryption, acknowledgment packets, and error correction further reduce effective throughput, typically to 70–90% of the raw link speed. For WAN links, latency and window size become limiting factors that this calculator does not model. Use this tool for planning data migrations, backup windows, and DR RTO estimates.