Remember these important October self-assessment tax return deadlines to prevent a surprise bill

Self-assessment taxpayers should keep in mind two crucial dates in October

October is a crucial month for taxes; forget about Halloween or the clocks going back.

In October, there are two important tax dates that impact self-employed individuals, new landlords, and those who wish to file the tax on paper.

While the pay-as-you-earn system allows most people to have their taxes automatically deducted, untaxed income must be self-assessed and reported to HMRC.

The self-employed, people with side jobs, investors, high-earning parents who repay Child Benefit, and landlords who receive rental income are all covered by this.

More people could fall under the self-assessment net as a result of frozen tax thresholds, so it's crucial to register and file on time to prevent the fear of an unexpected bill and associated penalties.

"Thousands of people sign up for self-assessment every year, and anyone who is new to self-assessment for the 2024/2025 tax year should register as soon as possible," stated Myrtle Lloyd, chief customer officer at HMRC.

These are the important dates for your October self-assessment.

The self-assessment registration deadline is October 5th.

Anyone starting their own business or receiving untaxed income, like rent, must notify HMRC and register for self-assessment by October 5th.

This pertains to earnings for the tax year 2024 - 2025.

To help you fill out a tax return, the tax collector will create a special taxpayer reference for you.

Online registration is available at Gov . uk.

Generally speaking, you must register for self-assessment if you are a new self-employed person or sole proprietor and have earned gross income of more than £1,000, received any untaxed income, including pension income exceeding £2,500, or received more than £1,000 from online trading or service provision.

Whereas investors might have to report dividends or capital gains over the tax allowances, landlords must also register if they receive income from real estate.

If you have previously notified HMRC of your status in prior years, you are exempt from registering.

The Low Incomes Tax Reform Group states that if you do not register by October 5th and you owe taxes, there may be penalties for failure to notify.

Depending on whether HMRC believes you are purposefully hiding income, this could be worth up to 100% of the tax due.

A 100 penalty will be applied if your tax bill is not sent on time, and you will then be penalized 10 times a day until you reach a maximum of 900.

There is an additional penalty of 5% of the tax owed or £300, whichever is higher, after six months. This penalty is the same after twelve months.

Additionally, there are penalties of five percent of the tax that is not paid within thirty, six, and twelve months.

Therefore, registering ahead of time will save you a great deal of time and money.

Even if you register after October 5th, HMRC will still send you a letter or email with a new deadline for filing your taxes. Typically, this is three months from the date specified in the letter or email.

You can determine if you must file a self-assessment tax return using a free online tool provided by HMRC.

Paper tax returns are due on October 31.

There are two due dates to be mindful of after registering for self-assessment, one of which is approaching.

By January 31, you can submit your return online.

But if you have chosen to file your taxes on paper, you have until the end of October to do so.

Your forms must be received by HMRC by October 31, 2025, at 11:59 p.m., or you risk a late filing penalty.

The best time to pay your taxes.

Any tax due for the 2024 - 2025 tax year must be paid by January 31, 2026, regardless of whether you file online or on paper.

In other words, you can either wait a few months or pay the tax due all at once if you file a paper form in October.

Whether you use online or paper forms, there are advantages to filing and paying any taxes due before the self-assessment deadline, even though you may prefer to keep your own money in the bank until your tax bill is due.

A self-assessment tax return completed early will guarantee that your payments on account are accurate, according to Samuel Mather-Holgate, independent financial adviser at Mather and Murray Financial. If you have underpaid, filing early may help you avoid extremely high interest rates. In this manner, there is no chance of paying too little and being hit with HMRC's exorbitant interest rates.

However, that is based on the assumption that self-employed people and landlords have easily accessible cash flow.

"I'm not sure many business owners are in a suitable position with the last Budget starting to really bite, increased National Insurance contributions hitting businesses, and financial squeezes from all directions," stated David Stirling, director of Mint Mortgages and Protection.