UK tradespeople: prepare your 2025–2026 Self Assessment before the January rush

Check the tax year and the filing route first

The return in question covers the tax year from 6 April 2025 to 5 April 2026. The normal paper deadline is 31 October 2026; the online deadline is 31 January 2027. A letter giving a different deadline or another exceptional situation should be checked against HMRC’s instructions. Do not use the online date to assume a paper return can wait until January.

Open a folder labelled with the tax year and the name of the business. Put the filing route and the person responsible on its first page. That simple separation matters when you are simultaneously issuing October 2026 invoices: current job administration and the return for the previous tax year are different work streams.

HMRC — Self Assessment deadlines

Establish whether you need to file and whether access works

If you are unsure whether a return is required, use HMRC’s checker. First-time filers need to register; people returning after a break may need to reactivate their account. The online filing page explains circumstances in which another route or commercial software is required. A limited company’s obligations should not be inferred from this sole-trader checklist.

Test access before asking your bookkeeper to prepare the final figures. Keep a private list of unresolved access or identity-verification steps and an internal completion date. The list needs the action and its owner, not your password or security answers. If an accountant is helping, use the proper authorisation arrangements rather than sharing your personal sign-in.

HMRC — check whether you need a tax return

HMRC — file Self Assessment online

Reconcile the job records with the accounting evidence

HMRC requires records of business income and expenses and the evidence supporting them. Depending on your circumstances, VAT, PAYE and personal-income records also matter. The records must identify business transactions. Traditional accounting requires additional year-end information; a bank total alone does not settle every accounting question.

A practical review starts with a list of jobs and invoice references. Match each entry to the relevant sales record, payment evidence and any credit note. Put missing supplier invoices in a separate action list. If a payment combines two jobs, annotate the match rather than creating a second sale. If a transfer is your own money moving between accounts, flag it for correct classification rather than treating every receipt as customer turnover.

HMRC — business records for self-employed people

Treat CIS deductions as a separate reconciliation

For CIS subcontractors, deductions are advance tax payments. HMRC asks sole traders and partners to complete Self Assessment as usual and report the deductions using the monthly payment and deduction statements. Limited companies use a different route. Do not treat a net bank receipt as proof that the gross sale has been recorded correctly.

Example: a fictional subcontractor has three contractor relationships. Build a table with contractor, statement month, gross amount, deduction and payment reference. Compare each row with the documents rather than applying a guessed percentage to all receipts. Ask the contractor for a missing statement and record that request. Resolve a mismatch before assuming it is a refund entitlement or an unpaid customer balance.

HMRC — CIS subcontractors: tax and deductions

Keep annual filing and Making Tax Digital tasks distinct

HMRC’s reminder explicitly says customers signed up to Making Tax Digital for Income Tax still need to submit this Self Assessment return in the usual way. Completing a current digital update should therefore not be marked as completion of the 2025–2026 annual return. Check the relevant tax-year task rather than relying on a generic “submitted” message.

On your office checklist, use separate rows for the annual return, the tax payment and any current-period digital updates. Record a submission reference only after the relevant system confirms it. A draft prepared in software is not the same thing as a filed return, and a completed return is not evidence that payment has been made.

HMRC — Self Assessment reminder, 23 October 2026

Make the next review small enough to finish

Set aside one session for missing documents, one for questions to your adviser and one for checking the final draft. For each uncertainty, write the evidence available and the specific decision needed. “Is this mixed-use purchase correctly apportioned?” is more useful than a folder named “tax problems”. This article does not decide which expense is deductible in your individual circumstances.

Vocalys can help you keep quotations and invoices clear as new work comes in. Dictate the intervention, check the amounts and retain the agreed document version. Want to spend less time rewriting your administrative documents? Discover Vocalys at vocalys.pro. Your accountant or tax adviser still needs the underlying records and the appropriate tax treatment.

Reusable job sheet

• Identify the 2025–2026 return
• Check paper or online deadline
• Verify registration and access
• Reconcile invoices and credit notes
• Collect CIS statements where relevant
• Resolve questions with the adviser
• Keep filing and payment confirmations

Tax year: […]
Filing route and deadline: […]
Responsible person: […]
Missing invoice or CIS statement: […]
Question for adviser: […]
Submission confirmation: […]
Payment confirmation: […]

The best use of the reminder is to turn scattered job paperwork into a short, reconciled file well before the deadline.