AMF ADVISORS BLOG
UK Self Assessment & Making Tax Digital Deadlines Explained (With a Free Calculator)
Between Self Assessment deadlines, payments on account, and the phased rollout of Making Tax Digital, HMRC’s rules for sole traders and landlords can be genuinely confusing. Here’s a plain-English breakdown, plus a calculator that works out your own dates.
HMRC’s Self Assessment rules haven’t changed much in years, but Making Tax Digital for Income Tax is rolling out in phases right now — and the two systems overlap in ways that trip people up. Below is a quick-reference summary, followed by a calculator that plugs in your own tax year and gives you exact dates. You can also explore our free VAT/sales tax and payroll calculators on the Free Tools page.
Quick Reference: Self Assessment & MTD
| What | Applies to | Deadline | If you're late |
|---|---|---|---|
| Registering for Self Assessment | Anyone newly required to file | 5 October following the end of the tax year you became liable | Potential "failure to notify" penalty |
| Paper tax return | Self Assessment filers using paper | 31 October following the tax year end | £100 initial penalty, then daily/6–12 month penalties |
| Online tax return & balancing payment | Most Self Assessment filers | 31 January following the tax year end | £100 initial penalty (filing) + 5% steps (payment) |
| Payments on account | Filers with tax liability over £1,000 not mostly collected at source | 31 January and 31 July | 5% of unpaid amount at 30 days, 6 & 12 months |
| MTD for Income Tax — quarterly updates | Sole traders/landlords above the qualifying income threshold | 7 August, 7 November, 7 February, 7 May | Separate points-based penalty regime |
Try It: Your Deadline & Penalty
Choose what you need below and get an exact date, plus an optional late-penalty estimate.
UK Self Assessment & MTD Deadline Calculator
Pick what you need below and get an exact due date — plus, where relevant, an estimated late penalty.
This tool gives a general estimate based on standard HMRC rules as of 2026 for the most common cases. It doesn't cover every situation (partnerships, non-resident rules, reasonable-excuse appeals, or MTD's separate points-based penalty regime for late submissions). Always confirm exact dates and amounts with HMRC or your accountant — or book a free consultation with AMF Advisors.
Further reading on gov.uk: Self Assessment deadlines, Self Assessment penalties, MTD for Income Tax eligibility, and using Making Tax Digital for Income Tax.
Not Sure If (or When) MTD Applies to You?
AMF Advisors keeps UK clients ahead of every Self Assessment and MTD deadline — and if you’re already behind, we’ll help you get compliant with as little pain as possible. Book a free consultation and let’s take a look.