Self-Assessment Tax Returns: A Simple Guide for Directors

Running a limited company means two separate sets of tax obligations, and confusing them is one of the most common mistakes directors make. Your company files a Corporation Tax return. You, personally, may need to file a Self-Assessment return. They have different deadlines, different forms, and different rules — and completing one does nothing to satisfy the other.

With the registration deadline for the 2025/26 tax year falling on 5 October 2026, now is a sensible time to check where you stand.

Do All Directors Have to File? A Common Myth

You will often hear that every company director must submit a Self-Assessment return. That is not strictly correct, and it is worth understanding why.

Being a director is not, by itself, a trigger. If all your income is taxed at source through PAYE and your dividends fall within the £500 dividend allowance, you may have no filing requirement at all.

In practice, however, most directors do need to file — because most take dividends above £500, and the allowance is now so small that even a modest distribution exceeds it. You will need to submit a return if you received dividends above the allowance, have untaxed income such as rent or interest, received benefits in kind, had a director's loan, made capital gains, or if HMRC has issued you a notice to file.

That last point is absolute. Once HMRC issues a notice to file, you must submit a return regardless of whether you think you needed to.

The Dividend Tax Rise You May Have Missed

This is the change most likely to affect directors this year. From 6 April 2026, dividend tax rates increased to 10.75% at the basic rate and 35.75% at the higher rate. The additional rate remains at 39.35%.

That is a two percentage point rise on both the basic and higher rates, and it lands on top of a dividend allowance that has already fallen from £5,000 to £500 over recent years.

The cumulative effect matters. The traditional low-salary-plus-dividends strategy still generally works, because dividends remain free of National Insurance and Corporation Tax on small profits is still 19%. But the margin is narrower than it was, and a structure set up several years ago and never revisited may no longer be the most efficient arrangement. If you have not reviewed your remuneration split since before April 2026, it is worth doing.

The Dates You Need

For the 2025/26 tax year, which ended on 5 April 2026:

5 October 2026 — deadline to register for Self-Assessment if you have never filed before. New directors frequently miss this one and pick up a penalty before they have submitted anything at all.

31 October 2026 — deadline for paper returns.

31 January 2027 — deadline for online returns, and the date any tax owed must be paid.

This is also when the first payment on account for the following year falls due, if applicable.

Payments on account catch out a lot of first-time filers. If your bill exceeds £1,000 and less than 80% of your tax was collected at source, HMRC requires two advance payments towards the following year — half on 31 January and half on 31 July. The first January can therefore bring a bill roughly one and a half times larger than expected. Plan for it rather than being surprised by it.

What Goes on the Return

The SA100 covers all your personal income for the tax year, not just the parts HMRC has not already seen. Your salary goes on the return even though it was taxed through PAYE.

You will also report dividends from your company and any other shares, benefits in kind taken from your P11D, bank and building society interest, rental profits, any self-employment income, pension contributions, Gift Aid donations, capital gains, and foreign or crypto asset income.

It is worth knowing that HMRC cross-checks your Self-Assessment against your company's accounts, its CT600, and any P11D filed. Mismatches between those records are one of the most common triggers for an enquiry.

Three Things Directors Regularly Get Wrong

Dividend timing. Many directors declare only the dividends that physically reached their bank account. But where a dividend has been properly voted by the board and minuted, it is generally taxable in the year it was declared — not the year it was paid. Getting this wrong can shift income into the wrong tax year entirely.

Director's loans. Money drawn from the company that is neither salary nor a properly declared dividend is a director's loan. If it remains outstanding nine months and one day after the company's year-end, the company faces a Section 455 tax charge, and there may be a benefit-in-kind charge on you personally if the balance exceeds £10,000. This is an easy problem to create accidentally and an expensive one to ignore.

Benefits in kind. Company cars, private medical insurance, and interest-free loans all carry a tax charge. They are reported by the company on a P11D and must then be carried onto your personal return. Directors who assume the company has dealt with it often find the figure missing from their own filing.

Penalties and Records

Missing the filing deadline triggers an automatic £100 penalty even where no tax is owed. Further penalties apply at three, six, and twelve months, and interest accrues on unpaid tax from the 31 January payment date.

HMRC expects you to keep supporting records for at least five years after the filing deadline — dividend vouchers, board minutes, P60s and P11Ds, bank statements, and evidence of any expenses or reliefs claimed.

Does Making Tax Digital Affect Directors?

Not yet, in most cases. MTD for Income Tax went live in April 2026 for sole traders and landlords with qualifying income above £50,000, with lower thresholds phasing in from 2027 and 2028.

Salary and dividend income from your own company does not currently bring you into scope. However, a director who also has rental property or self-employed income above the threshold may well be caught by those other income sources, so it is worth checking rather than assuming.

How Crown Payroll Services Can Help

Your personal tax position and your company payroll are two halves of the same decision. The salary you draw affects your National Insurance, your Corporation Tax, and your Self-Assessment bill all at once — and the recent dividend rate rise has changed the arithmetic for a lot of directors.

If you would like your remuneration structure reviewed before the next filing deadline, call us on 01942 644864 or email hello@crownpayrollservices.co.uk.