Self Assessment for Company Directors: When You Do (and Don't) Need to Register

It’s a common assumption that becoming a company director automatically means filling in a Self Assessment return every year.

Because it doesn’t.

If your only income is a salary taxed through PAYE, you don't have to register at all.

So, when do you have to register?

For most people, it's dividends.

Small salary, topped up with dividends, is how most company directors pay themselves, and if that's you, here's where the line sits:

• Dividends within the £500 tax-free allowance: nothing to report.
• Dividends between £500 and £10,000: you don't necessarily need to register for full Self Assessment. You can call HMRC or update your details online and ask them to collect the tax through your PAYE tax code instead, as long as you're employed or on a pension. This has to happen between 5 April and 5 October.
• Dividends over £10,000: you must register for Self Assessment and file a return.

Most directors land in that middle bracket without realising a full return isn't automatically required.

Dividends are not the only one route in. A few other things mean you have to register too:

• Self-employed income over £1,000, say a side consultancy alongside the company
• Rental income over £2,500
• Capital gains over the £3,000 annual exempt amount
• Foreign income
• Savings interest over £10,000
• The High Income Child Benefit Charge, if you or your partner earns over £60,000 and either of you claims Child Benefit

A high salary alone doesn't put you here - if none of the above applies and PAYE is your only income, the number on your payslip doesn't change anything.

HMRC can also just send you a notice to file.

If that happens, you have to comply, even if you don't think any of this applies to you. You can ask for it to be withdrawn afterwards, but only once you've shown them that none of the above fits your situation.

If you’re not sure where you stand, HMRC has an online checker that asks a few questions and tells you whether you need to register.

How to register

The form is SA1. Form called CWF1 is only for people newly self-employed, so most directors don't use it. If you're both a director and self-employed, use CWF1 instead.

Have your NI number ready before you start and registering online takes a few minutes. You'll also need a Government Gateway account, which you can set up during the same process if you don't already have one.

Your UTR then arrives by post, usually within 10 working days, or around 21 if you're abroad.

You'll also get an activation code, sometimes in the same letter, sometimes separately. It's only valid for 28 days, so activate your account as soon as it arrives. You need both the UTR and an activated account before you can file anything.

If you have filed before, you likely still have a UTR even if you can't find it, HMRC can look it up. You'll just need to reactivate your account, which means waiting for a new activation code.

Deadlines, and what happens if you miss one

The deadline to register is 5 October following the end of the tax year.

So 5 October 2026 for anyone with 2025/26 income to report for the first time.

The well-known £100 fine is for filing your return late, not for registering late. Registering after 5 October instead risks a "failure to notify" penalty, based on how much tax you still owe, and it only applies if you also haven't paid in full by 31 January.

The £100 penalty is for a late return specifically, and it's automatic, even if you owe nothing. After three months it's £10 a day up to £900. After six months, another 5% of the tax due or £300, whichever is more. The same again at twelve months. Both penalties can apply in the same year, so it's best not to test either deadline.

Keeping dividend records clean matters too, because if you can see exactly what's been paid out and when, working out which bracket you're in  is a five-minute job, not a guess.

It's the same clean paper trail that stops a dividend turning into an accidental director's loan if the paperwork lags behind the payment.

A dedicated business account keeps a clear, dated record of every payment that goes out, so checking that against your own dividend records is straightforward. Open a business account and start that record from day one.

Register in good time and the wait is on HMRC's end, not yours. The form itself takes a few minutes. The UTR letter is what takes the days.