Enter a data size and a link rate. Get the transfer time — with bits and bytes handled correctly, plus an optional efficiency factor for real-world overhead.
Link rates are quoted in bits per second (Mbps, Gbps). File sizes are in bytes (MB, GB). There are 8 bits in a byte, so a "100 Mbps" link moves at most 12.5 MB/s. Forgetting the ×8 is the single most common transfer-time mistake.
So a 10 GB file over a perfect 100 Mbps link: 10 GB × 8 = 80 Gb, divided by 0.1 Gbps = 800 seconds (about 13.3 minutes). This tool does that conversion automatically and lets you set an efficiency factor, because real throughput never hits the line rate.
Storage and OS reporting disagree: a "1 TB" drive is 10¹² bytes (decimal), but Windows shows it as ~0.91 TiB (binary, 2⁴⁰). The unit selector offers both so your estimate matches whichever your source uses.
TCP/IP headers, ACKs, retransmits, and congestion control mean you rarely see 100% of the line rate. For bulk transfers over a clean path, 90–95% is typical; over lossy or high-latency links it can be far lower (see the bandwidth-delay product tool).
About 800 seconds (13.3 min) at the theoretical line rate; closer to ~14–15 min at realistic efficiency.
Protocol overhead, latency, server limits, and shared links. Set efficiency to ~90% for a more realistic figure.
No. 1 GB = 10⁹ bytes; 1 GiB = 2³⁰ ≈ 1.074×10⁹ bytes. Pick the unit that matches your source.