Bandwidth and Download Time Calculator

How long a transfer actually takes on a given link, and how many concurrent streams a connection carries before it is the bottleneck.

In megabits per second. A gigabit port is 1000.

TCP/IP framing and retransmits. 5-10% on a healthy wired link.

typical

In gigabytes.

In megabits per second. 4K video is roughly 25.

A link run to 100% has no room for anything interactive.

Reset
7 min Transfer takes
29 Streams the link carries
That transfer
Transfer takes 7 min
Concurrent streams
Usable after headroom 736.0 Mbps
Streams the link carries 29
Those streams use Megabits per second. 725.0 Mbps
Spare after them 195.0 Mbps

Megabits are decimal and so are gigabytes here, because that is how link speeds and drive capacities are both quoted. Substituting 1024 anywhere in this chain gives an answer about 7% out that looks entirely plausible.

Overhead covers framing and ordinary retransmission, not a saturated link. Once a connection is at capacity, latency and loss climb and the effective rate falls further than any fixed percentage predicts — which is what the headroom field is for.

Nothing here is sent anywhere; the numbers live in the page address.