The time it takes for a loose tooth to fall out depends on how loose the tooth is to begin with.
If the tooth is just slightly loose then it may never fall out on it's own which is a good thing if you don't want to lose the tooth.
Some teeth normally wiggle a bit and may seem like they are loose but that's okay and they should not fall out.
If the tooth is really loose then it may fall out within a few days to a few weeks or so.
If the tooth is very loose and you can pull it out easily then it's okay to do that but don't force it.
If a tooth is loose enough to come out on it's own it will eventually but it just takes some time.
I had loose teeth fall out within a few weeks but for some people it may take a month or more.