What tax deadlines should sole traders put in their calendar?

Why sole traders need a “tax calendar” (and what it should do for you)

If you’re a sole trader, your tax life is rarely a single deadline. It’s a rhythm of recurring dates that keep your records accurate, your payments predictable, and your stress levels lower than they’d otherwise be. A proper tax calendar does three things: it reminds you to file returns on time, it nudges you to set aside cash before you need it, and it gives you regular prompts to keep bookkeeping up to date so you’re not trying to rebuild a year of transactions in one frantic weekend.

The right dates for you depend on where you’re based and what taxes apply to your business. In the UK, the core deadlines most sole traders encounter revolve around Self Assessment, payments on account, and (for some) VAT and payroll. You might also have sector-specific or local obligations, but the essential pattern is the same: record steadily, review periodically, file accurately, and pay on time.

This article is designed to help you build a calendar you can actually use. Rather than dumping a list of dates with no context, it explains which deadlines matter, who they apply to, what happens if you miss them, and what to do ahead of time so each due date becomes routine instead of a scramble. Use it as a checklist to populate your digital calendar with repeating reminders and buffers.

Start with your foundation: your accounting habits and “buffer reminders”

Before you add any official tax dates, decide how you’ll run your reminders. Most sole traders benefit from three layers:

1) The official deadline — the real “must-do” date.

2) A preparation reminder — typically 4 to 6 weeks beforehand, prompting you to gather records, reconcile accounts, and check anything unusual.

3) A cash reminder — usually monthly or quarterly, prompting you to transfer money into a “tax pot” account so large bills don’t ambush your cash flow.

If you only add the official deadline, you’re relying on last-minute willpower. If you add the preparation and cash reminders, you’re building a system. The system is what helps you stay compliant even when business gets busy.

Self Assessment: the core cycle for most UK sole traders

For many UK sole traders, the primary tax process is Self Assessment. That includes registering (if you’re newly self-employed), keeping records, filing a tax return each year, and paying income tax and National Insurance based on your profits.

Registering for Self Assessment (new sole traders)

If you’ve just started trading, one of the first calendar items isn’t a payment date — it’s registration. Registering for Self Assessment tells HMRC you need to file a return. If you don’t register when required, you can run into problems later because you may still owe tax even if you didn’t receive a prompt to file.

Add a calendar reminder to register as soon as you start trading, plus another a few weeks later to confirm it’s done and that you have the login details you’ll need. If you’re setting up systems from scratch, it’s also worth scheduling time to choose bookkeeping software (or a spreadsheet approach), open a separate business bank account (highly recommended), and create a simple receipt capture routine (photo, email forwarding, or app scan).

Tax year end (5 April) and why it matters even if you file later

The UK tax year runs from 6 April to 5 April. Even though you typically don’t file and pay immediately on 5 April, that date is still important because it defines what income and expenses go into which year. Many mistakes happen when invoices, payments, or expenses get assigned to the wrong tax year, especially if you’re catching up on bookkeeping months later.

Put 5 April in your calendar with a reminder to “close the year in your records.” You don’t need a full final tax calculation that day, but you do want to:

• Ensure all income for the year is recorded and categorized correctly.

• Ensure allowable expenses are recorded with evidence (receipts, invoices, mileage logs).

• Reconcile bank transactions so you can see what’s missing.

• Note any one-off items that might affect your profit (large equipment purchases, grants, refunds, unusual costs).

Also add a reminder for early April to request any information you might need from clients, platforms, or banks, especially if you rely on year-end statements or reports.

Self Assessment filing deadlines: paper vs online

Sole traders commonly file online, but it’s worth understanding both deadlines because they explain why some people mention October while others mention January.

Paper return deadline: 31 October following the end of the tax year.

Online return deadline: 31 January following the end of the tax year.

For example, for the tax year ending 5 April 2025, the paper deadline is 31 October 2025 and the online deadline is 31 January 2026.

Even if you intend to file online, putting both dates in your calendar can be useful: 31 October becomes your “soft deadline” for being fully up to date. If you aim for October, January becomes a buffer rather than a panic point.

The 31 January deadline: filing and paying (and why it can be a double hit)

31 January is the big one for most sole traders. It’s typically the deadline to:

• Submit your online Self Assessment tax return.

• Pay any tax and National Insurance due for the previous tax year.

• Make your first “payment on account” for the current tax year (if you’re required to make payments on account).

This is why people sometimes describe January as a “double bill.” If your profits have increased, the January payment can be substantial because it includes what you owe for the year just finished, plus an advance instalment toward the current year.

In your calendar, don’t just add “Tax due.” Add a series of reminders: one in early December to do a profit estimate, one in early January to confirm the final figures, and one a week before 31 January to initiate payment. Bank transfers can take time depending on method, and it’s risky to leave it to the last day.

Payments on account: the dates that catch people out

Many sole traders pay tax through payments on account. This usually applies when your Self Assessment bill is above a certain threshold and you’re not paying most of your tax at source (like through PAYE). Payments on account spread part of your bill across two instalments, based on your previous year’s tax.

The typical schedule is:

1st payment on account: 31 January

2nd payment on account: 31 July

These are not optional “nice to have” payments. They are part of how the system collects tax in advance. If your income goes down, you may be able to reduce payments on account, but doing so requires care because reducing too far can leave you with interest or a balancing payment later.

Put 31 July in your calendar with equal importance to 31 January. July arrives quickly, and because it falls in the middle of the year (and often during holidays), it can be overlooked.

Balancing payments: what happens when the estimate doesn’t match reality

When you make payments on account, you’re essentially paying an estimate. When you file your return, HMRC calculates the actual amount owed for that year. If your payments on account weren’t enough, you’ll owe a balancing payment. If they were too high, you may be due a refund or have the excess credited to future liabilities.

This is another reason your January deadline is so important. It’s where the tax for the previous year is finalized and the advance payments for the current year begin. Adding a reminder in November or December to do a “tax projection” can help you avoid unpleasant surprises.

VAT: deadlines to add if you’re registered (or close to the threshold)

Not every sole trader is VAT registered, but if you are, VAT introduces another set of recurring calendar dates. The specific due dates depend on your VAT accounting period (often quarterly) and your filing method. Many businesses file VAT returns online.

VAT returns are usually due one month and seven days after the end of your VAT period, though your exact arrangement can vary. The key point for your calendar is that VAT deadlines repeat more frequently than Self Assessment, and the cash can be significant because you’re collecting VAT from customers and holding it until you pay it over.

If you’re VAT registered, add these recurring reminders:

• End of each VAT quarter: “Reconcile VAT period and check invoices/expenses.”

• 2 weeks after quarter end: “Prepare VAT return draft.”

• 1 week before submission deadline: “Submit VAT return and schedule payment.”

Also add a monthly reminder to transfer the VAT portion of your sales into a separate “VAT pot” account. This is one of the most effective ways to prevent accidental spending of money that isn’t really yours.

Keeping an eye on VAT registration threshold

Even if you’re not VAT registered, you may need to monitor your taxable turnover to see if you’re approaching the registration threshold. If you cross it, you may need to register and start charging VAT. That change affects pricing, invoicing, cash flow, and admin.

Put a quarterly calendar reminder to review your rolling 12-month turnover. Don’t wait until your accountant mentions it or until you suddenly realize you’ve grown. Proactive monitoring lets you plan price changes and communicate clearly with customers.

Payroll deadlines if you employ staff (or pay yourself via payroll)

Some sole traders employ staff, and some may run payroll for other reasons. If you operate PAYE, you’ll have regular reporting and payment obligations. Payroll deadlines can be frequent and unforgiving, so your calendar should be very explicit about them.

Common calendar items include:

• Each payday: “Run payroll and submit FPS (Full Payment Submission) on or before payday.”

• Monthly: “Pay PAYE/NIC to HMRC by the due date.”

• Year-end payroll tasks: “Prepare P60s and finalize payroll year.”

Because payroll involves people’s wages and tax deductions, many businesses schedule payroll earlier than payday to allow time for errors to be spotted and fixed. A practical approach is to set a “payroll prep” reminder 5–7 days before payday, then a “submit and pay” reminder on payday.

Student loan, High Income Child Benefit Charge, and other personal add-ons

Sole traders often discover that their tax bill includes more than basic income tax. Depending on your circumstances, your Self Assessment can also include things like student loan repayments, or other charges that are calculated through the return. These aren’t separate deadlines so much as “components” of what’s due on the main payment dates, but they can change your cash flow planning.

Add a reminder in December or early January to review any personal factors that might affect your bill. If your situation changed during the year — for example, income changes, benefits changes, or a move into a different repayment plan — it’s better to know before you press submit.

Business rates and local obligations (where relevant)

Some sole traders operate from premises rather than from home, and may have business rates or local authority obligations. These are not universal, but if they apply to you, they’re often billed on a schedule with instalments. Missing them can cause penalties and cash flow disruption.

If you receive a bill that’s paid monthly, set a recurring monthly reminder for the payment date and a quarterly review reminder to ensure the amount still matches your bill (rates can change, and adjustments happen).

Corporation Tax and Companies House deadlines (only if you later incorporate)

This article is aimed at sole traders, but many people switch from sole trader to limited company as they grow. If that’s on your horizon, it’s worth knowing that incorporation changes your compliance calendar significantly. Corporation Tax deadlines, Companies House confirmation statements, accounts filing deadlines, and potentially dividends documentation all come into play.

If you’re considering incorporation, add a planning reminder rather than tax deadlines: schedule a meeting with an accountant or advisor well before the end of a tax year so you can understand how timing affects what you pay and what paperwork is required.

A practical “core calendar” template for most UK sole traders

Here’s a straightforward set of entries many sole traders can put in their calendar right away. You can adapt it based on your specific situation:

Monthly reminders

Bookkeeping catch-up (monthly): Block 60–120 minutes to reconcile your bank account, categorize transactions, upload receipts, and invoice any late-paying clients. Doing this monthly makes year-end far easier.

Tax pot transfer (monthly): Move a percentage of income into a separate account for tax. The exact percentage depends on your profit margin and other income, but the habit is what matters.

VAT pot transfer (monthly, if VAT registered): Transfer the VAT portion you’ve collected so it’s always available when due.

Quarterly reminders

Quarterly review (every 3 months): Review profit, set-aside amounts, and upcoming liabilities. This is the moment to spot that January could be heavy and to adjust early.

VAT quarter end and submission cycle (if VAT registered): Add end-of-quarter reconciliation and the submission/payment deadline as separate events.

Turnover threshold check (if not VAT registered): Review rolling 12-month turnover.

Annual reminders

5 April: Tax year ends. Add reminders to ensure records are complete and organized.

May/June: Gather year-end statements and reports. This is an excellent time to begin drafting your return.

31 October: Paper filing deadline. Use as a “soft deadline” even if filing online.

December: Tax projection for January. Confirm cash reserves and likely payment on account requirements.

31 January: Online filing deadline and payment date, including balancing payment and first payment on account where applicable.

31 July: Second payment on account where applicable.

How to set reminders so you never rely on memory

A calendar entry that says “Tax due” isn’t enough. Your future self will open it and still feel unsure. Each deadline should have a short checklist in the description field. Here’s an example for 31 January:

Reminder name: “Self Assessment filing + payment due”

Description checklist: Confirm income totals, confirm allowable expenses, check mileage log, check home office apportionment (if used), confirm any other income, review student loan status (if relevant), review payments on account for reasonableness, submit return, schedule payment, save submission receipt and payment confirmation.

Then add supporting reminders such as “Draft return by 15 December” and “Finalize figures by 10 January.” The goal is to turn a single scary date into a sequence of small tasks.

Cash flow planning: make the deadlines financially boring

Tax becomes stressful mostly when the money isn’t ready. A calendar is useful, but it’s even better when it’s paired with a simple cash system. Many sole traders use one or more of these approaches:

Separate bank accounts: Keep a dedicated tax savings account. Some people also keep a separate VAT account.

Percentage-based transfers: After each client payment, transfer a set percentage to tax savings. If your income is irregular, this can be more reliable than a monthly fixed amount.

Quarterly true-ups: Review whether you’ve saved enough based on actual profit rather than revenue. If you’ve had a high-expense quarter, you may not need to save as aggressively. If you’ve had a very profitable quarter, top up.

To support this with your calendar, schedule a “tax pot review” in early December and early June. These moments align well with the big Self Assessment payment in January and the payment on account in July.

Record-keeping deadlines: not official, but vital

Some of the most important “deadlines” for sole traders aren’t imposed by HMRC on a specific date, but they’re critical to getting your numbers right. If you don’t set your own internal deadlines, you end up with missing receipts, forgotten mileage, and guesswork.

Add repeating reminders for:

Mileage log update: Weekly or monthly. Mileage is easy to forget and hard to reconstruct accurately later.

Receipt capture: Weekly. Take photos or scan receipts and store them in one place.

Invoice review: Weekly or fortnightly. Check which invoices are overdue and follow up. This improves cash flow and helps ensure income is recorded correctly.

Bank reconciliation: Monthly. Match your bookkeeping to your bank account so you can spot missing items quickly.

What to do if you miss a deadline

Even with the best calendar, life happens. If you miss a filing or payment deadline, act quickly rather than avoiding it. The longer you leave it, the more likely you are to face penalties, interest, or additional complications. The practical steps are:

• File as soon as possible if you’re late filing.

• Pay as soon as possible if you’re late paying, even if you can’t pay the full amount (paying something can reduce further charges).

• Keep records of what you did and when, including payment confirmations.

• If you believe you have a reasonable excuse, document it clearly and take advice on how to proceed.

Most importantly, after you’ve dealt with the immediate issue, adjust your calendar system. Add earlier reminders, add a “catch-up day,” or change your process so one busy week doesn’t derail a whole year.

How to customize your tax calendar based on your business type

Two sole traders can have very different calendars even within the same tax system. Here are examples of customizations that often help:

If you’re a freelancer paid by international clients: Add monthly reminders to check currency conversions and ensure your invoices and bank receipts match what you’re recording. Exchange rates and fees can cause small discrepancies that add up.

If you’re in retail or hospitality: Add weekly reminders to reconcile card payments, cash takings, and fees. These businesses can have higher transaction volume, so short cycles are better.

If you use subcontractors: Add reminders to collect invoices and verify details before payment, so your expense records are complete.

If you have seasonal income: Add pre-season planning reminders to increase your tax pot contributions during peak months so quieter months don’t leave you short for January or July.

A simple checklist of dates to put in your calendar today

If you want a quick starting point, here’s a condensed checklist you can add immediately and refine later:

• 5 April: Tax year end — reconcile and organize records.

• 31 October: Paper Self Assessment deadline (use as a soft target).

• 31 January: Online Self Assessment deadline + payment due (and first payment on account if applicable).

• 31 July: Second payment on account if applicable.

• Monthly: Bookkeeping catch-up + tax pot transfer.

• Quarterly: Profit review + VAT/turnover check (as relevant).

• If VAT registered: VAT quarter end dates + VAT submission/payment deadlines (per your VAT periods).

• If you run payroll: Payroll run dates, reporting submissions, and monthly payment deadlines.

Make it sustainable: the “two-hour rule” and the “one-screen dashboard”

A calendar works best when it’s paired with routines that keep you within two hours of being up to date. If you let bookkeeping drift for months, deadlines become emotionally heavy and practically difficult. The “two-hour rule” means you aim to be able to bring your records fully up to date within two hours at any point in the year. That forces you to capture receipts, reconcile transactions, and invoice consistently.

The “one-screen dashboard” is a simple view — in a spreadsheet, an accounting app, or even a notes document — showing four numbers: total income year-to-date, total expenses year-to-date, estimated profit, and tax pot balance. Update it monthly. When your dashboard and your calendar work together, you can see both the time deadlines and the money readiness.

Final thoughts: the best tax calendar is the one you actually follow

Sole trader tax deadlines can feel intimidating when they’re vague, distant, and only surface when a letter arrives or a friend mentions them. But when they’re in your calendar — with preparation reminders, cash reminders, and short checklists — they become manageable. The goal isn’t to become obsessed with tax; it’s to make compliance routine and predictable.

Start with the core Self Assessment cycle: the tax year end on 5 April, the filing target on 31 October, the main filing and payment date on 31 January, and the second payment on account on 31 July. Then layer in VAT and payroll only if they apply to you. Add monthly bookkeeping and tax-saving reminders, and you’ll turn tax deadlines from last-minute emergencies into simple admin tasks you already planned for.