Can I claim a CIS refund without an accountant?

Can I claim a CIS refund without an accountant? Yes. A CIS refund is part of your own Self Assessment tax return, which you can file yourself. For the 2026-27 tax year you can file from 6 April 2027, and HMRC repays any excess deductions. No. A sole trader's CIS refund is claimed on their own Self Assessment tax return. You can file that return yourself online. HMRC works out the tax you owe, takes off your CIS deductions and repays any excess. Your UTR, your HMRC sign-in details, every monthly payment and deduction statement for the tax year, a total of your business costs with receipts, and your UK bank details so HMRC can pay the refund. It can be if you have several years to catch up, a letter from HMRC querying your figures, a van or equipment to claim, or other income to fit in. For one year of simple CIS work, you can usually file it yourself. Read the full answer, with every source, at rightotax.co.uk.