Only days to file and pay as self-assessment deadline looms

Those who have yet to file their online self-assessment tax return and settle any tax due have only a few days left to do so before facing a financial penalty.

Any online tax returns submitted after 31 January will be subject to a late filing penalty from HMRC. People who fail to pay any tax owed by this deadline will also receive a separate penalty.

According to HMRC in early January, 5.65 million people had yet to submit their self-assessment tax return. In contrast, 6.36 million people had made their submissions by then¹.

There is an initial £100 penalty for those failing to file their tax return in time, rising to £10 a day after three months. There are further charges of up to 5% if a return has still not been filed after six or 12 months.

If someone fails to pay any tax due by 30 days after the 31 January deadline, they will face a penalty of 5% of the unpaid tax. If still unpaid then another 5% penalty will be levied at six months and a further 5% at 12 months, in addition to interest accrued on any unpaid tax.

More than a million people missed the self-assessment deadline last year according to HMRC, incurring steep penalties as a result².

Claire Trott, head of advice at St. James’s Place, says: “Even if you don’t have full or complete information, it is better to submit your return as provisional and update it with complete or more accurate information at a later date. Ignoring the deadlines can be very costly and will quickly add up, not to mention the additional stress this will cause.”

Tax returns are typically used by the self-employed, those in business partnerships, individuals who have to pay capital gains tax on assets sold, and in some cases those who have untaxed income such as from renting out a property or foreign income.

If you are unsure if you need to submit a tax return to HMRC, you can find out by checking here.

Sources

¹UK government – January 2026
²UK government – February 2025

SJP Approved 27/01/2026