Last-Minute Self Assessment Tips for Busy UK Taxpayers

Advice for procrastinators filing close to the 31^st January deadline!

If you’re reading this in mid-to-late January, there’s a good chance one of two things is happening:

1. You’ve been meaning to do your Self Assessment tax return for weeks…
2. You’ve just remembered the deadline is 31^st January and are now in full panic mode.

First of all, don’t worry. You’re not alone. Every January, thousands of UK taxpayers scramble to submit their Self Assessment at the last possible moment. The good news is with the right approach, you can still file accurately, avoid penalties, and get it off your to-do list without losing your sanity.

The Self Assessment deadline for most UK taxpayers is 31^st January 2026. This is the final date to submit your online tax return for the 2024/25 tax year and to pay any tax owed to HMRC. This may include income tax, National Insurance contributions for the self-employed, and payments on account for the current tax year.

Missing the deadline automatically results in a £100 late filing penalty, even if no tax is due. Additional penalties and interest can apply if the delay continues, which is why submitting your return on time should always be the priority.

When time is short, it’s important to focus on the information that matters most. You don’t need perfectly organised records to file your Self Assessment tax return, but you do need accurate figures.

Make sure you have:

• Your Government Gateway login details
• Employment income information such as a P60 or P45
• Total self-employed income for the tax year
• Bank interest and dividend income
• Pension contribution details
• Student loan information, where applicable

If you’re self-employed, bank statements and invoices are often enough to calculate income and expenses accurately, even at short notice.

Rushing your Self Assessment return often leads to missed expenses, which can mean paying more tax than necessary. Even if you’re filing close to the deadline, it’s worth spending time reviewing what you can legitimately claim.

Allowable expenses may include:

• Office costs such as phone, internet, and stationery
• Travel and mileage expenses
• Software subscriptions and digital tools
• Marketing and advertising costs
• Professional fees, including accountancy services
• Use of home as office, where appropriate

Taking the time to include these expenses correctly can significantly reduce your overall tax bill.

Mistakes are more likely when filing under pressure. Some of the most common errors we see on last-minute Self Assessment tax returns include entering turnover instead of profit, forgetting additional income streams, and claiming personal expenses as business costs.

Other frequent issues include incorrect pension contribution figures, missing student loan repayments, and unexpected payments on account. Reviewing the final summary carefully before submitting your return can help prevent problems later on.

If you’re worried about paying your Self Assessment tax bill by 31^st January, it’s important not to delay submitting your return. Late filing penalties are often more severe than interest charged on late payments.

If you can’t pay in full:

• Submit your Self Assessment return on time
• Pay what you can afford
• Contact HMRC to discuss a Time to Pay arrangement

Filing on time keeps penalties to a minimum and gives you more flexibility when dealing with HMRC.

Most taxpayers submit their Self Assessment tax return using HMRC’s online system. It allows you to save your progress, review calculations, and access guidance throughout the process.

January is the busiest month of the year for HMRC, so it’s advisable to submit your return earlier in the day rather than waiting until the final hours of the deadline. This helps avoid delays caused by system traffic or last-minute technical issues.

If your tax affairs involve self-employment, rental income, multiple income sources, or uncertainty around expenses, professional support can be extremely valuable, even at the last minute.

An accountant can:

• Review your tax return for accuracy
• Ensure you’re claiming all allowable deductions
• Reduce the risk of HMRC penalties
• Advise on payments on account and cash flow
• Deal with HMRC on your behalf

Getting expert help close to the deadline can often save time, money, and stress.

Once your Self Assessment tax return is submitted, it’s worth thinking about how to make the process easier next year. Many taxpayers experience January stress simply because records haven’t been kept throughout the year.

Keeping your finances organised, setting aside money for tax regularly, and reviewing your position well before January can make Self Assessment far more manageable. Working with an accountant earlier in the year can also help you plan ahead and avoid last-minute pressure.

Get in touch with us if you’ve been thinking about receiving that support from an accountant.

Email us info@future-cloud.co.uk

Your friendly, forward-thinking accountants!

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