Interest rates on refunds, underpaid tax and outstanding tax
Interest rate on underpaid tax and refunds for personal taxpayers
The interest surcharge is 0.39 per cent per year, calculated from 1 July 2017 to the due date of the first instalment of underpaid tax in 2018.
If you have paid too much assessed advance tax or prepayment deductions before the end of the income year, you will receive interest on the excess amount you have paid at the rate of 0.39 per cent, calculated from 1 July 2017 until you receive your tax settlement notice in 2018.
In the case of the repayment of additional advance tax or assessed advance tax paid no later than 31 May of the year after the income year, interest will be added at the rate of 0.39 per cent per year from 31 May 2018 until the tax settlement notice is sent to the taxpayer.
Interest rate on underpaid tax and refunds for non-personal taxpayers
The interest surcharge on underpaid tax for non-personal taxpayers (limited companies, etc.) is 0.39 per cent per year, calculated from 15 March 2018 and through until the due date for the underpaid tax.
If too much advance tax is paid by 31 May, interest will accrue at the rate of 0.39 per cent per year of the excess amount paid, calculated from 15 March 2018 until the tax settlement notice is sent to the taxpayer