Download & Transfer Time
How long a file takes at a given link speed, the speed needed to finish in time, or how much moves in a given time — bits and bytes, MB and MiB kept apart.
The transfer time as hours, minutes and seconds, the payload rate in MB/s and MiB/s, and the same file on common link speeds side by side, with the overhead you enter.
Example: A 50 GB file on a 100 Mbps line takes 1 h 6 m 40 s at 12.5 MB/s; on 1 Gbps, 6 m 40 s. With 10 % overhead, 1 h 14 m.
Bits per second,
bytes per file.
The one division behind transfer time, the two unit traps that make most estimates wrong by eight or by five percent, and what real links lose on top.
The arithmetic
Time = bytes × 8 ÷ bits per second. Link speeds are sold in bits (a 100 Mbps line moves at most 12.5 megabytes a second) and files are measured in bytes, so the ×8 is where most mental estimates go wrong. The three questions on the page are the same equation solved for time, for speed, and for size.
MB or MiB
A file manager on Windows shows binary units (1 MiB = 1,048,576 B, often labelled “MB”); network gear, drive makers and macOS use decimal (1 MB = 1,000,000 B). The difference is 4.9 % at mega, 7.4 % at giga and 10 % at tera. The unit selector accepts both and the results show both, so the figure you compare against is the one you meant.
Overhead
TCP/IP and Ethernet headers take roughly 3–6 % of a link at full-size packets and more at small ones; wireless, VPN tunnels and slow far ends take more. The page assumes none — enter the figure that matches your path, as a percent of the link speed lost, and the time stretches accordingly. Bandwidth-Delay Product covers the separate latency limit on a single TCP stream.
What the number does not settle
This is the link-speed bound. The server’s upload rate, disk speed at either end, throttling, contention on shared media and packet loss can each make the real transfer slower; none is modelled. Inputs stay in your browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
Last reviewed 18 September 2026. How results are checked: How we verify.