The California Department of Tax and Fee Administration Aug. 1 announced interest rates effective from Jan. 1, 2020 to June 30, 2020, for excise, and sales and use tax purposes. The interest rate for unpaid or underpaid taxes is 8 percent and is based on the rate charged by the IRS, plus 3 percent. The credit rate applied to refunds is 2 percent. The rates don’t apply to the International Fuel Tax Agreement. [Cal. Dep’t of Tax & Fee Admin., Interest Rates for Unpaid or Underpaid Taxes, 08/01/19]

Reference: View Source Document.