Is the speed split when multiple devices are connected to the router?

Question

Computer networks

Let's say the Internet speed provided by the provider to the user is 256 Kbps.
If several devices are connected to the router, for example 3 (1 PC and 2 smartphones), will the speed be divided between them?
For example, each 85.3 Kbps?

Answer 1

If one is downloading, it will have a speed of 256, if 2 are downloading at the same time (and each is downloading one file in one stream), then the speed will be 128. If one downloads torrents in 100 streams, and the second one watches a video from YouTube, then the first one will take almost the entire strip. This is very rude.
Very roughly - the speed is divided by the number of TCP connections.

Answer 2

Differently.
Usually, the average SOHO router by default tries to divide the bandwidth approximately equally.
Key words here - tries and approximately.
It is not always possible for him to divide, and the concept of equally is very loose - equally between users or flows generated by the user.
As a result, one user, if desired, can clog the channel by 99%.
If you have a narrow channel and such a problem arises, you need to buy a more functional router that can do shaping - that is, traffic separation according to clearly described rules. Of the inexpensive devices of this kind, Mikrotik can be recommended.
Setting up shaping requires knowledge and skills, and the process is not easy, and therefore not cheap. And the load on the router is large.
Therefore, it makes sense to do it when there is no way to increase the connection speed.