— Article

Self-Assessment Deadline Checklist: 2026 Edition

15 January 2026·6 min readSelf-AssessmentHMRCTax

Filing your Self-Assessment doesn't have to be a New Year scramble. Here's the 7-step checklist we send to every Ledgerly Pro user in early January.

1. Confirm you actually need to file

You generally need to file a Self-Assessment if you earned more than £1,000 in self-employed income, received untaxed dividends above £500, or had foreign income.

2. Gather your income evidence

  • Invoices issued in the tax year
  • Platform payout statements (PayPal, Stripe, Patreon)
  • P60s from any employment

Ledgerly Pro automatically prepares this list for you — open the Tax Estimator and click Export Self-Assessment summary.

3. Collect allowable expenses

The most-missed UK allowable expenses for self-employed people:

ExpenseRule
Home officeUse of home as office — £6/week flat rate or actual costs
Mileage45p/mile first 10,000 miles, 25p thereafter
PhoneBusiness proportion of monthly bill
Software & subscriptions100% if business use

4. Check your tax code

Login to your HMRC account and verify the code reflects your situation.

5. Calculate payments on account

If your tax bill is over £1,000, you'll owe payments on account on top — half of next year's projected bill on 31 January, half on 31 July.

6. File before the deadline

The 2026/27 deadlines are:

  • 31 October 2026 — paper filing
  • 31 January 2027 — online filing (and balance payment)
  • 31 July 2027 — second payment on account

7. Set up a tax pot

The single biggest stress-reducer is paying tax-set-aside money into a separate account every month. Ledgerly Pro estimates your liability live so you know exactly how much.


Next read: How VAT works for sole traders

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