Child support is governed by guidelines in virtually every state, as a result of Federal law.  The formulas for guidelines differ from state to state, however.

In California, the guidelines calculate specific support figures based on the after tax income of the parents and their respective time share with the child or children.  the formulas are so complicated that they are rarely calculated without a computer.  There are websites where you may make estimates of support based on information available to you.  Because accurate calculations require accurate an complete income and tax information, you should not rely on these estimates in agreeing to support.

The preparation of the financial documents on which support is based can be an artform.  Without experience, it is difficult for anyone to advise you how income will be calculated, and what tax effects will be used.  You should get competent advice.

If you are unable to afford an attorney, or wish to handle child support matters on your own, California has established Departments of Child Support Services [DCSS] to assist you.  Its  services are free to the public [without an earnings test].

Because DCSS is a state agency, it has certain collection powers not available to private attorneys, such as collecting from lottery winnings, tax refunds, and suspension of driver's and employment licenses.  It's cases are handled in special departments in front of commissioners.  DCSS lacks the manpower to do the investigation necessary to find assets or prove income for anyone other than w-2 employees, you may still want to have a private lawyer conducting discovery and arguing your case, even if you want DCSS to monitor the collection of support.  Many certified specialists have the cases hear in these same courts so they can keep the DCSS remedies available to assist their clients, while still providing experienced service.