Ohio Revised Code Title LVII. Taxation § 5735.11

(A) If the tax or any portion of the tax imposed by this chapter, whether determined by the tax commissioner or the motor fuel dealer, is not paid on or before the date prescribed in section 5735.06 of the Revised Code, interest shall be collected and paid in the same manner as the tax upon the unpaid amount, computed at the rate per annum prescribed by section 5703.47 of the Revised Code, from the date prescribed for payment of the tax to the date of payment or to the date an assessment is issued under section 5735.12 or 5735.121 of the Revised Code, whichever occurs first. Interest may be collected by assessment in the manner provided in section 5735.12 or 5735.121 of the Revised Code. All interest shall be paid in the same manner as the tax and shall be considered as revenue arising from the portion of the tax described in division (A) of section 5735.05 of the Revised Code.

(B) Interest shall be allowed and paid upon any refund granted in respect to the payment of an illegal or erroneous assessment imposed under this chapter from the date of the overpayment. The interest shall be computed at the rate per annum prescribed by section 5703.47 of the Revised Code.