UK small business tax calendar: Key dates & deadlines (2026)

There's a moment every small business owner in the UK eventually recognises. The first tax year ends and the first self-assessment looms. The first VAT quarter closes and the deadline lands faster than expected. The first PAYE month arrives and the £100 penalty notice from HMRC hits the mat before the postage stamp has dried. And somewhere in the middle of all of that, an accountant mentions Making Tax Digital, and suddenly the rules you'd just figured out are about to change again. This time from 6 April 2026.

The UK tax calendar is difficult to keep pace with. Different filings sit under different agencies. Personal tax runs on a 6 April to 5 April cycle. The government's own financial year runs from 1 April to 31 March. VAT deadlines depend on your stagger group. Corporation Tax sits on your company's own accounting period. Companies House works on a different schedule entirely. P60s, P11Ds, Class 1A NIC, payments on account each have its own date, its own form, and its own penalty for missing it.

This guide is for the UK small business owner, sole trader, landlord, freelancer, or limited company director who wants the full tax calendar in one place with the dates that matter, the rules behind them, what changed for 2026, and how modern accounting software handles every one of them without anyone having to think about it.

What the UK tax year is & why it's not the calendar year

The UK personal tax year runs from 6 April to 5 April the following year. For example, the 2026/27 tax year starts on 6 April 2026 and ends on 5 April 2027. This 6 April quirk is a historical artefact leftover from when Britain switched from the Julian to Gregorian calendar in 1752; the tax year was nudged forward by 11 days to preserve revenue, and never moved back.

The government's own financial year runs from 1 April to 31 March. Corporation Tax rate changes are typically announced for these dates.

Your limited company's financial year is your own, set by your accounting reference date with Companies House. This is where most small business confusion starts. Corporation Tax deadlines depend on your accounting period, not the personal tax year or the government year.

For a small business owner running both personal tax (self-assessment) and company tax (corporation tax), three calendars are running in parallel. Good accounting software merges this complexity into one dashboard.

The complete UK small business tax calendar (2026)

Here is the full year of UK small business deadlines, organised by month. Bookmark this section, or export the dates into your calendar.

 January 2026   

February 2026   

March 2026  

April 2026 

May 2026   

June 2026   

July 2026 

August 2026

October 2026 

November 2026   

December 2026   

January 2027 — The cycle restarts 

Deadlines based on your company's accounting period (not the tax year)

If you run a limited company, these deadlines move with your company's own accounting reference date and not the personal tax year. Use this table to work out yours.

For example, a company with a 31 March 2026 year end must pay Corporation Tax by 1 January 2027, file Annual Accounts with Companies House by 31 December 2026, and file the CT600 with HMRC by 31 March 2027.

How modern accounting software handles every UK tax deadline

The case for HMRC-recognised cloud accounting software in 2026 isn't about saving time—it's about not missing a deadline. Here's what good UK accounting software does to handle the calendar above.

Continuous digital recordkeeping 

Bank feed integrations pull transactions automatically. Receipts are captured by photo through the mobile app. VAT, expenses, and income are categorised against HMRC categories in real time. By month-end, your books are not a project, they're a review.

Automatic VAT return preparation and submission 

The software calculates VAT from the underlying transactions, prepares the return in MTD format, and submits directly to HMRC. The £90,000 threshold is tracked automatically; you get a warning when you approach it.

MTD for Income Tax quarterly updates 

For sole traders and landlords in scope from April 2026, the software generates each quarterly update from the digital records you're already keeping. Review, approve, submit to HMRC—done in minutes.

Self-assessment preparation (Sole traders) 

For sole traders below the MTD threshold (or above) completing their final declaration, good UK accounting software pulls together all income and expense data into a Self-Employment report (SA103F or SA103S equivalent), calculates tax owed, and either generates the return for filing or submits it directly to HMRC.

Corporation Tax (CT600) and Final Accounts filing for limited companies 

This is where HMRC's portal closure on 1 April 2026 becomes a forcing function. From April 2026, limited companies need commercial software to file CT600 returns. Zoho Books UK now supports direct CT600 filing to HMRC and Final Accounts filing to Companies House for micro-entities, available on all paid plans: statutory accounts under FRS 105, CT600 return, and Companies House submission, all from the same accounting data with no duplicate entry.

Payroll integration 

For businesses with employees, payroll integration handles PAYE/NIC calculations, generates FPS submissions, produces P60s in May and P11Ds in July, and calculates Class 1A NIC for the July deadline. The PAYE journal entries post to your books automatically.

Deadline reminders and dashboards 

The best UK accounting software shows every upcoming deadline in a single dashboard—VAT due dates, self-assessment payments on account, Corporation Tax payment, P11D, and Companies House confirmation statement. There's no more wondering what's next.

Audit-ready records 

HMRC requires that records be kept for at least six years (longer for certain businesses). Cloud accounting software retains everything indefinitely, properly indexed, and ready for any HMRC enquiry.

What to look for in UK accounting software in 2026

Here's the evaluation framework for any UK small business choosing accounting software in 2026.

HMRC recognition for MTD 

The software must be on HMRC's list of recognised MTD-compatible software for both VAT (already mandatory) and for Income Tax (mandatory from April 2026 for the £50,000+ wave). Anything not on the list creates compliance risk.

Direct HMRC submission 

The software should submit VAT returns, MTD updates, and (for limited companies) CT600 returns directly to HMRC without manual exports.

Companies House integration 

For limited companies, direct filing of statutory accounts to Companies House, without re-keying the underlying numbers, is now a meaningful efficiency gain.

UK-specific functionality 

Reverse charge VAT, partial exemption, EC sales lists, VAT margin schemes, CIS, IR35—UK accounting has specific quirks that generic global accounting software handles poorly.

Bank feed coverage with UK banks 

The right software will offer direct integrations with major UK banks, including HSBC, Barclays, NatWest, Lloyds, Santander, Starling, Monzo, Tide, Revolut. Open banking has made this near-universal, but verify coverage for your specific bank.

Self-assessment support for sole traders 

For sole traders, the software should generate the Self-Employment report and (ideally) submit the final declaration to HMRC directly.

Pricing that works for small businesses 

UK accounting software prices vary widely from free options to £40+/month for SME packages. Watch for hidden costs like per-user fees, per-filing charges, payroll add-ons, VAT submission limits, support tiers, and multi-currency surcharges.

Free plan for sole traders

Some UK accounting software now offers free plans specifically for sole traders. Zoho Books offers a free plan for UK sole traders with full MTD for Income Tax compliance, digital recordkeeping, invoicing, expense tracking, and HMRC submissions, making MTD compliance cost-free for small operators.

Multi-currency and language support:

For UK businesses operating internationally, software that supports multiple currencies and languages is invaluable for managing global operations efficiently.

Data security and UK data residency 

UK businesses handling personal data are subject to UK GDPR. Look for ISO 27001 certification, SOC 2 Type II, encryption at rest and in transit, and clarity on where data is stored. For businesses with sensitive client data like accountants and those in healthcare, legal UK or EU data residency is increasingly a procurement requirement.

Accountant collaboration 

Modern UK accounting software lets accountants log in with their own credentials, file on behalf of clients, manage multiple clients from one interface, and use agent filing for VAT and Income Tax submissions. This is now table stakes.

Mobile apps 

Ensure there are iOS and Android apps with full functionality to invoice on the go, capture expenses by photo, check VAT position, and view your dashboard. The mobile experience matters for owners who aren't sitting at a desk.

Where Zoho Books fits for UK small businesses

Zoho Books UK was built to handle every UK tax deadline, beyond the daily bookkeeping, to the year-end CT600 filing. Here's how it maps to the framework.

HMRC-recognised for MTD

Zoho Books has been on HMRC's recognised MTD software list since 2019 for VAT, and is now also recognised for MTD for Income Tax. Quarterly MTD updates can be submitted directly from the platform.

Free plan for sole traders

Unique among major UK accounting platforms, Zoho Books offers a free plan specifically for sole traders that includes digital recordkeeping, invoicing, expense tracking, bank feeds, and full MTD for Income Tax compliance at no cost. For sole traders approaching the £50,000 threshold from April 2026, this removes the compliance cost barrier entirely.

CT600 and Final Accounts filing

Available on all paid plans from January 2026, you can generate FRS 105 micro-entity statutory accounts, submit directly to Companies House, and file the CT600 to HMRC, all from one set of accounts. This is particularly relevant given HMRC's portal closure on 1 April 2026.

Self-assessment for sole traders

The Self-Employment report (SA103F/SA103S equivalent) is generated directly from your transaction data and is ready to use for your self-assessment filing.

Full VAT support

All schemes are covered including Standard, Flat Rate, Annual Accounting, Cash, and Margin. MTD-compliant returns are submitted directly to HMRC.

Native UK bank feed coverage

Connections to all major UK banks are available through open banking with daily automatic transaction syncing.

Native integration with the Zoho ecosystem

Zoho Books connects natively with Zoho Inventory for stock-driven businesses, Zoho CRM for sales-led workflows, Zoho Expense for employee expense management, so your accounting isn't isolated from the rest of how the business runs.

Pricing

Zoho Books has transparent per-organisation pricing with annual billing discounts and a free plan for sole traders. There are no hidden per-submission charges.

Accountant collaboration

Accountants can be added to your Zoho Books account with appropriate permissions, file MTD submissions on your behalf, and manage multiple clients from a single accountant view.

Data security

The platform has ISO 27001, ISO 27701, ISO 27017, ISO 27018, SOC 2 Type II, and GDPR certifications. Data is encrypted in transit and at rest. UK customer data is also stored in Zoho's European data centres.

For a UK small business owner, be it the sole trader, landlord, freelancer, or limited company director, the combination of HMRC recognition, a free plan for sole traders, CT600 filing, MTD readiness, and the Zoho ecosystem integration makes Zoho Books one of the most complete options to stay in compliance with the 2026 UK tax calendar.

Common UK small business tax mistakes (and how good software prevents them)

Here are a few common mistakes noticed across UK small business tax compliance.

Treating MTD for Income Tax as something to think about later

The 6 April 2026 deadline has come and gone. Sole traders and landlords above £50,000 who haven't moved to MTD-compatible software now face quarterly submission failures and the new points-based penalty regime. The right time to switch is now.

Missing the 19th of the month for PAYE

PAYE penalties for missed payments start at 1% of the unpaid amount and rise quickly. The recurring 19th-postal/22nd-electronic deadline catches owners who manage payroll manually. Software automation removes this risk.

Forgetting P11D

Benefits in kind including the likes of company cars, private medical insurance, employer loans, and gym memberships must be reported on P11D by 6 July with Class 1A NIC due by 22 July. Many small business owners don't realise the obligation applies until they get a penalty notice.

Ignoring the £90,000 VAT registration threshold

Once you cross it, you have 30 days to register, and registration is effective from the first day of the second month. Late registration triggers interest, penalties, and HMRC enquiries. Software that tracks turnover on a rolling 12-month basis catches this early.

Missing the second payment on account on 31 July

January's deadline gets attention but July's doesn't. The 31 July payment on account is the same amount as January's, due six months later. Calendar reminders and software dashboards prevent this slip.

Filing Companies House and HMRC separately for limited companies

For the same underlying accounts there are two filings and two opportunities for mismatch. Integrated software that files both from one set of data eliminates the reconciliation risk.

Underestimating recordkeeping requirements

HMRC requires records to be kept for at least six years. Paper records get lost. Spreadsheets corrupt. Cloud accounting software solves this by default.

A simpler way to handle the UK tax calendar

The UK small business tax calendar in 2026 isn't simpler than it was in 2025; it's more demanding. Making Tax Digital for Income Tax arrives in April. HMRC's free CT filing portal closes in April. The penalty regime tightens. Quarterly submissions replace the once-a-year timeline for an ever-growing share of sole traders and landlords. By 2028, qualifying income as low as £20,000 will pull operators into mandatory digital reporting.

The UK small businesses that handle all of this well in 2026 aren't doing more manual work. They've picked HMRC-recognised cloud accounting software that absorbs the complexity with automatic VAT calculations, MTD quarterly updates, direct submissions to HMRC and Companies House, integrated payroll and expense flows, a free plan for sole traders, and Corporation Tax filing for limited companies. They set it up cleanly once, and the calendar handles itself.

Zoho Books was built to be exactly that: A single accounting platform that handles your business finances as well the compliance, integrates with the broader Zoho ecosystem, and gives sole traders, landlords, freelancers, and limited company directors a way to stay compliant without paying for tax compliance to become a full-time concern.

A simpler way to keep your books is a simpler way to run a UK small business. Try Zoho Books for free (including the dedicated free plan for sole traders) and experience what UK accounting looks like when it's built for the realities of running a small business in 2026.

Frequently asked questions

When does the UK tax year start and end? 

The UK personal tax year runs from 6 April to 5 April the following year. The 2026/27 tax year starts on 6 April 2026. The UK government's own financial year runs from 1 April to 31 March, separate from the personal tax year and used for setting Corporation Tax rates.

When is the self-assessment deadline for 2025/26? 

The online self-assessment deadline for the 2025/26 tax year is 31 January 2027. This is also when any balancing payment for 2025/26 is due, plus the first payment on account for 2026/27. The paper deadline is earlier: 31 October 2026. A £100 automatic penalty applies for filing even one day late, regardless of whether tax is owed.

What's the VAT registration threshold in the UK in 2026? 

The VAT registration threshold remains £90,000 for 2026 (raised from £85,000 on 1 April 2024). Once your taxable turnover exceeds £90,000 in any rolling 12-month period, you must register for VAT within 30 days. The deregistration threshold is £88,000.

What are the Corporation Tax rates for limited companies in 2026? 

Per GOV.UK, Corporation Tax rates for the financial year starting 1 April 2026 are: 19% small profits rate for companies with profits at or below £50,000; 25% main rate for companies with profits above £250,000; and Marginal Relief for profits between £50,000 and £250,000, producing an effective rate that gradually increases. These rates have been unchanged since 1 April 2023.

When does Making Tax Digital for Income Tax start? 

This began on 6 April 2026. It's mandatory for sole traders and landlords with qualifying gross income above £50,000 in the 2024/25 tax year. The threshold reduces to £30,000 from 6 April 2027 and £20,000 from 6 April 2028.

Is Zoho Books HMRC-recognised for MTD? 

Yes, Zoho Books UK is HMRC-recognised for both MTD for VAT (since 2019) and MTD for Income Tax (in scope for the April 2026 mandate). Quarterly updates can be submitted directly from the platform to HMRC.

Does Zoho Books offer a free plan for sole traders? 

Yes, Zoho Books UK offers a free plan specifically for sole traders that includes digital recordkeeping, invoicing, expense tracking, bank feeds, self-assessment preparation, and full MTD for Income Tax compliance (all at no cost). This is unique among major UK accounting platforms.

When are P11D forms due? 

They are due 6 July, following the end of the tax year. For the 2025/26 tax year, P11D and P11D(b) forms are due to HMRC by 6 July 2026, with copies provided to employees by the same date. Class 1A National Insurance on the benefits is due by 19 July (postal) or 22 July (electronic).

When are payments on account due? 

Payments on account are due in two instalments: 31 January (first payment) and 31 July (second payment). Each is 50% of the previous year's tax liability. The 31 January payment is paid alongside the balancing payment from the previous tax year and the self-assessment filing.

What happens to HMRC's free Corporation Tax filing portal in 2026? 

HMRC's free Corporation Tax online filing portal closed for new submissions on 1 April 2026. Since that date, all CT600 filings must go through HMRC-recognised commercial software. Zoho Books launched CT600 and Final Accounts filing in January 2026 as a direct response.

When is the deadline for filing annual accounts at Companies House? 

Annual accounts must be filed with Companies House within nine months of the end of your company's accounting period. The CT600 (Corporation Tax return) to HMRC is due within 12 months of the accounting period end, and Corporation Tax payment is due 9 months and 1 day after the accounting period ends.