How Fast Is 100 Mbps?
Last reviewed 2026-11-01
What 100 megabits per second can carry, in megabytes and in everyday tasks, and what it does not guarantee.
The unit
100 Mbps is 100 million bits per second, or 12.5 decimal megabytes per second if the transfer really holds that rate. In binary mebibytes that is about 11.9 MiB/s.
A 1 GB file (decimal) is 8,000 megabits. At a steady 100 Mbps the theoretical time is 80 seconds. Overhead makes real copies longer. The download calculator can apply an efficiency factor.
What it covers
One 4K stream is often planned around 25 Mbps, so 100 Mbps can cover a few streams if they are the only traffic. A video call wants upload as well. 100 Mbps down says nothing about a 10 Mbps upload.
Latency is separate. A 100 Mbps line with a large buffer can still feel late in games. Measure both.