If you are doing business in California, you are subject to our tax laws. We consider you to be "doing business" if you meet any of the following:Retailers engaged in business in California must register with the California Department of Tax and Fee Administration (CDTFA) and pay the state's sales tax. A successor or purchaser of a business or stock of goods must withhold a sufficient amount of the purchase price to cover the sales tax liability of the seller. Stay tax-compliant with this California sales tax guide for businesses. From sales and use tax to collections and filing taxes, let Polston Tax guide you. A Note on Timely Filing: Business Taxes are due January 1st of each year and are delinquent if not paid on or before the last day of February of each year. Learn the requirements for state and local business licenses in California and what steps you need to take to get a business license in California. What is a business license? All businesses located in or doing work in Berkeley are required to have a business license and pay business license taxes.