What is the Self Assessment deadline if I only pay the High Income Child Benefit Charge?

Is there one deadline, or two different clocks?

GOV.UK splits the High Income Child Benefit Charge into PAYE and Self Assessment. Parents who have never filed a return often miss the 5 October ‘tell HMRC’ date because it lives on the register-for-Self-Assessment pages, not on the Child Benefit claim form.

You must use Self Assessment if you need a tax return for another reason (GOV.UK’s example is becoming self-employed), or if it is later than 31 January in the year after the tax year you need to pay for. GOV.UK’s example: for the tax year starting 6 April 2025, after 31 January 2027 the payment has to go through Self Assessment.

Which dates apply if HICBC is the only reason I file?

The register page repeats 5 October 2026 for anyone who needs a return for the previous tax year and has not sent one before, or registered before but did not need a return for 2024 to 2025. If you register after that date, HMRC sends a letter or email with a different filing deadline — 3 months from the date on that letter or email — but the deadlines page still says tax for that year is due by 31 January 2027.

GOV.UK on the HICBC Self Assessment page: you may get a penalty if you need to pay through Self Assessment but do not register for it, or do not declare Child Benefit on your tax return. No pound figure is given on that page.

How do I work out which route I still have time for?

1. 1
   Name the tax year the charge is for A UK tax year runs 6 April to 5 April. The letter or calculator result is for a named year, not ‘this month’s Child Benefit’.
2. 2
   Check whether you already send a tax return If you already file for self-employment, savings, or another reason, GOV.UK says you must put the charge on that return. PAYE is not a substitute.
3. 3
   If you do not usually file, watch 5 October Tell HMRC by 5 October following the tax year by registering for Self Assessment. That is how GOV.UK says you notify them when HICBC is the reason you need a return.
4. 4
   If it is still on or before 31 January and you have no other SA reason, PAYE is still listed The PAYE service needs your adjusted net income, a partner’s adjusted net income if you have a partner, the National Insurance number of any partner who received Child Benefit in the last tax year, and the dates of those relationships. You cannot save progress in that service.
5. 5
   After 31 January following the tax year, use Self Assessment only Register if you have not, file the return, and pay on the Self Assessment deadlines. Switching later from Self Assessment to PAYE is a phone call to HMRC, and only if you no longer need a return for another reason.

When does GOV.UK still allow PAYE instead of a return?

All three PAYE conditions have to be true: you do not need a tax return for another reason; you are paying the charge for the current or previous tax year onwards; and it is on or before 31 January after the tax year you need to pay for. Miss any one of those and the PAYE page sends you to Self Assessment.

If you have previously completed a return only for this charge, GOV.UK says you can ask to leave Self Assessment and register for PAYE by phone. You still need the same income, partner National Insurance and relationship-date details.

In shortIn short: 5 October is the tell-HMRC date if you are new to Self Assessment; 31 January is the last day PAYE can collect a just-ended tax year; after that the charge is a Self Assessment job. Use the official calculator first, then the PAYE or register pages — not a guessed fine.