How much time will you serve on a 12 year sentence in California prisons?

In California, the actual time served on a 12-year sentence can vary based on factors like good behavior credits and parole eligibility. Generally, inmates can earn credit for good behavior, which allows them to serve about half of their sentence. Therefore, with good behavior, one might serve approximately 6 years before being eligible for parole. However, specific circumstances and laws can affect the exact time served.