It comes down to the dollar amount of the theft, your criminal history, how pissed off the victim is and if you are cooperating with the prosecution or are you making them fight to convict you.
If you are a first time offender and the crime is petty theft, you might not do any time. If you have a bunch of priors and this crime is in the tens of thousands or more, you will probably get 1-3 years - but this is strictly a guess as we do not have near enough information to really give you a firm estimate.
https://www.inmateaid.com/ask-the-inmate/i-have-two-theft-charges-already-im-being-charged-with-a-felony-how-much-time-do-you-think-ill-have-to-do#answer
Accepted Answer Date Created: January 20,2015