Self Assessment deadlines for 2026/27: what taxi drivers need to know

Bookmark this one. The 2026/27 tax year runs from 6 April 2026 to 5 April 2027, but the deadlines that go with it don’t land until much later - which is exactly why they catch drivers out.

The key dates

• 5 October 2027 - deadline to register for Self Assessment, if you started self-employment at any point during 2026/27 and haven’t registered before.
• 31 October 2027 - paper tax return deadline.
• 31 January 2028 - online tax return deadline, and the deadline to pay any balancing tax you owe for 2026/27.
• 31 January 2027 and 31 July 2027 - payments on account, if they apply to you (see below).

What “payments on account” actually means

If your tax bill is more than £1,000 and less than 80% of your tax was collected at source (which covers almost every self-employed driver), HMRC assumes you’ll owe roughly the same again next year, and asks you to pay half of it upfront, twice: once by 31 January and again by 31 July. It’s not an extra tax - it’s next year’s bill, paid early, in two instalments. It’s also exactly why your first proper tax year as a driver can involve a genuinely large payment in January: a full year’s tax, plus the first payment on account for the year after, both due on the same date.

What happens if you miss a deadline

Missing the filing deadline is expensive even if you owe no tax at all:

• £100 automatic penalty for a late return, straight away
• +£10 a day after 3 months, up to 90 days (so up to another £900)
• +5% of the tax due, or £300, whichever is more - at both the 6-month and 12-month marks

Paying late is a separate penalty on top: 5% of the unpaid tax at 30 days, 6 months, and 12 months late, plus interest accruing the whole time. None of this is worth risking for the sake of a phone call or an email a few weeks earlier than you’d planned.

One thing that’s about to change for some drivers

If your turnover is £50,000 or more, a new system called Making Tax Digital for Income Tax started applying to you from 6 April 2026, replacing the once-a-year return with quarterly digital updates and its own, different penalty structure. We’ve covered exactly what that involves, and whether it applies to you, in our Making Tax Digital guide.

Don’t wait for January to think about any of this

The drivers who find Self Assessment stressful are almost always the ones who leave everything until the deadline is close. The ones who don’t, are the ones who’ve had someone keeping an eye on these dates for them all year.

Every plan we offer includes your return prepared and submitted on time, every year, with reminders well before any deadline gets close. Ring Michael on 07799 414972 for a free, no-obligation chat.