Accountants for limited companies and sole traders

When are limited company accounts due at Companies House?

A private limited company must file its annual accounts at Companies House within 9 months of the end of its accounting period, pay its Corporation Tax 9 months and 1 day after the period ends, and file its Company Tax Return (CT600) within 12 months. First accounts covering more than 12 months have a longer deadline: 21 months after incorporation.

Companies with taxable profits over £1.5 million pay Corporation Tax in quarterly instalments instead, starting during the accounting period (GOV.UK: paying in instalments). Notice that the tax is due almost 3 months before the return. That is why we work out your bill well before the payment date, not at the last minute.

What are the actual dates for my year end?

Here are the deadlines for the two most common year ends, worked out from the GOV.UK rules above. They assume a private company filing accounts that are not its first, with taxable profits up to £1.5 million.

For every other UK tax date this year, see our tax deadlines 2026/27 page.

What happens if company accounts are filed late?

Companies House charges an automatic penalty, and it doubles if the accounts are late two years in a row (Companies House guidance).

HMRC penalties for a late Company Tax Return are separate. It is £200 if the return is late, a further £200 at 3 months and 10% of unpaid tax at 6 and 12 months. The flat penalties rise to £1,000 each if returns are late three times in a row (GOV.UK: Company Tax Return penalties). The flat penalties were doubled at Budget 2025, and the new amounts apply to returns with a filing date on or after 1 April 2026 (HMRC policy paper).

Do I need an accountant as a sole trader?

Not by law: you can file your own Self Assessment return. What a sole trader accountant adds is getting the figures right and the timing planned. We turn your income and expenses into accounts, work out your taxable profit and National Insurance, and use those figures for your Self Assessment tax return. We also tell you what to pay and when, including payments on account, and check whether Making Tax Digital for Income Tax applies to you. Our self-employed tax calculator estimates the income tax and National Insurance on your profit, and our Making Tax Digital checker shows if and when MTD applies to you.

These are the main figures for sole traders in the 2026/27 tax year (6 April 2026 to 5 April 2027). Income tax bands shown are for England, Wales and Northern Ireland; Scotland has its own bands for non-savings income (Scottish Income Tax).

If you are in Making Tax Digital this year, HMRC will not give penalty points for late quarterly updates in 2026/27, but you still have to keep digital records and send every update before you can file your return (GOV.UK: MTD penalties). Our Making Tax Digital guide explains the rest, and our personal tax service covers the return itself.

Why plan tax alongside your accounts?

Because most tax-saving decisions have to be made before your year end, not after it. Once the year has closed, the accounts can only record what happened. Looking at your numbers a few months before the year end gives you time to act. These are the 2026/27 rules we look at most often.

• Where your profit lands. Companies pay Corporation Tax at 19% on profits up to £50,000 and 25% above £250,000. In between, marginal relief means each extra pound is effectively taxed at 26.5% (HMRC manual CTM03925). These figures assume a 12-month accounting period and no associated companies: the limits are divided between associated companies and reduced for shorter periods.
• When you buy equipment. The Annual Investment Allowance gives a 100% deduction for up to £1 million a year of qualifying plant and machinery, though not cars (GOV.UK). Buying before the year end rather than just after brings the relief forward by a year.
• How you take money out. From 6 April 2026, dividends above the £500 allowance are taxed at 10.75% in the basic rate band and 35.75% in the higher rate band, up 2 percentage points on 2025/26 (GOV.UK). The right mix of salary, dividends and pension contributions is worth reviewing every year. Our guide to paying yourself as a director sets out the options, and our payroll service can run a director's salary through PAYE.
• Pension contributions. The pension annual allowance is £60,000 for 2026/27 (GOV.UK). It tapers for the highest earners, down to £10,000, and money purchase contributions are capped at £10,000 for anyone who has already flexibly accessed a pension. For most directors it leaves plenty of room to plan.
• Costs from before you started. A new company can deduct revenue expenses incurred up to 7 years before it started trading, if they would have been allowable once it was trading (Corporation Tax Act 2009, section 61).

Our corporation tax service covers the return and the planning in more detail, and the corporation tax calculator shows what your company could owe.