1.26 Ark. Code R. 51-807(b)
Although an Arkansas taxpayer receives an extension of time to file his or her Arkansas individual income tax return, this extension does not extend to the payment of any income tax due the State of Arkansas. A taxpayer should file a "tentative" return in the form of estimated tax voucher #5 on or before the original due date for filing the return (May 15 for calendar year taxpayers) and include with the return payment in full of any tax estimated to be due the State of Arkansas. Interest at the rate of ten percent (10%) per annum will be assessed on all unpaid tax due the State of Arkansas from the original due date for filing the return (May 15 for calendar year taxpayers). A "failure to pay" penalty will also be assessed on all unpaid tax due the State of Arkansas from the original due date for filing the return. However, no "failure to file" penalty will be assessed where the taxpayer has properly requested an extension of time to file his or her Arkansas individual income tax return.
1.26 Ark. Code R. 51-807(b)