Different disc sizes reported by LVM to the FS sizes

[Gabriel M Dragffy]

In the LVM section of the ubuntu partitioner it detects my logical
volumes. But the information given doesn't make sense to me.

For example it will report one partition as being 520M but it reports
the FS as 545M. And on another (the one mounted as /home) it reports the
size as being 30G but the FS as being 32G. Is this normal? It seems to
work OK, but I don't understand why it might say this.

Gabe