How long does it take to register to ISO 9000?

The time it takes to get ISO 9001 registered are varies. But it is talking
months here, not weeks. For one thing, you have to keep running your
business. You cannot simply shut down while getting registered.
The entire process can be broken down into the following general
phases:
a. Implementing the ISO 9000 system.
b. Operating it for the minimum time. (A minimum of three, and
preferably six, months before registration audit.)
c. Selecting a registrar. This can be done during the registration
process, to save time.
d. Interval between application and registration audit. This depends
on the registrar’s backlog.

The time it takes to implement the ISO 9000 system depends in large
part on where you are when you start. If you already have any of the
following, implementation time should be relatively short:
a. A documented quality system of any kind that is active, meaningful,
but not necessarily compliant with any particular standard.
b. Resources temporarily dedicated solely to implementing the system.
c. The guidance of a good consultant

If you are starting from square one, implementation can take a long
time. (Unless you can shut down operations while implementing—but
who can do that?) Here are some other factors that can extend the
time it takes:
a. Multiple locations.
b. Head count.
c. Whether or not you are design responsible.
d. Corporate turmoil.
e. Lack of ongoing, consistent, persistent top management commitment.
This exhibits itself in a host of symptoms, including lack of
sufficient resources, other issues taking priority, vacillation, failure
to pay attention, failure to learn and understand, and failure
to lead.
All that being said, experience has shown the following:
a. On average, the shortest interval for the entire process—from
launch through registration audit—seems to be around 6 to 9
months.
b. At the other extreme, it’s been known to take 18 to 24 to 36
months, even with significant resources and full management
commitment.
On average, for the typical organization (whatever that is), you are
looking at 10 to 18 months to get the job done.