There are several things to consider and agree on when starting with the OKR program in the organization. One of them is OKR cycle length.
The two most common cycles are a quarter and a year. The length is inseparably tied to Goal Scopes, or in more common lingo - at which level will you be deploying OKRs.
You can create OKRs for your company's vision. In fact, you can frame your vision to BE the Objective! If the vision is interpreted to be something we strive to be in 5-10 years, then that is the longest OKR cycle you create.
When you do that, you have a context for "company-level" OKRs. As already mentioned, Agile Tools uses the term "scope" to classify the concepts on which to create goals. OKRs in an organizational scope (alias, at org level) can be created not only for a year but also for two or three years.
The more tactical goals are usually created per quarter; at least, that is in all the books. But recently, field experience shows that having cycles of four months brings some benefits over quarterly ones. Agile Tools offers you that cycle length out of the box. We also provide six months cycle option so that no one is deprived.
The shortest implemented cycle is one month for those that want to stretch the limits. Choosing such a short cycle has some downsides, including goal-setting fatigue.
What is essential is that all cycles must be synchronized at least once a year. Otherwise, the alignment can be challenging to achieve.