It is a mandatory 60 months if on the day you file your past 6 months of income is over the median income for a family of your size.
The minimum period is always 36 months unless you repay 100% of the debt that files a proof of claim.
If you are a below median income family at the time you file you may choose any period between 36-60 months.
Disclaimer: This answer does not constitute legal advice. I am admitted in the States of New York, New Jersey and Massachusetts only and make no attempt to opine on matters of law that are not relevant to those three States. This advice is based on general principles of law that may or may not relate to your specific situation. Facts and laws change and these possible changes will affect the advice provided here. Consult an attorney in your locale before you act on any of this advice. You should not rely on this advice alone and nothing in these communications creates an attorney client relationship.
If you make less than the median income, you may qualify to pay off your Chapter 13 in 36 months. But you may wish to make smaller monthly payments to accomplish your Chapter 13 goal, so you may take as long as 60 months.
If you make more than median income, you must propose a 60 month plan or pay off 100% of your debt.
Hope this perspective helps!
The minimum chapter 13 plan is 36 month, the maximum is 60 months. In most states, you must go 60 months if your income exceeds the median for a household of your size. Otherwise, you get to pick the term within the 36 to 60 month range.