CalCal supports two ways to file income tax: MTD for Income Tax (quarterly updates for newer mandated years) and legacy Self Assessment (the classic annual SA return). This guide covers the legacy SA workflow in the app. If HMRC has moved you to MTD, start with MTD for Self Assessment in CalCal instead.
Where to find your tax return
- Open the menu → Tax (Tax Years).
- Select the tax year you need.
- Legacy years show the classic submission steps — sync figures, complete forms, calculate, submit.
- MTD years show quarterly obligations under Income Tax — different workflow.
Typical legacy SA workflow
1. Sync from your bookkeeping
If you use CalCal for daily entries, sync figures pulls income and expenses from your records into the SA form. Tax-only plans may need figures entered directly in the tax screens.
2. Complete SA forms
Work through each required form section — employment, self-employment, property, etc. CalCal generates forms from HMRC schemas. Use helpsheets where needed: SA form helpsheets.
3. Pre-population (optional)
Connect to HMRC to import information they already hold — employment income, etc. You will sign in on the HMRC website and return to CalCal. If connection fails, see HMRC authentication failure.
4. Check the calculation
Run HMRC’s calculation in CalCal and review tax due before submitting. If figures surprise you, see HMRC calculation mismatches and Personal allowance.
5. Submit to HMRC
Enter your Government Gateway credentials when prompted (separate from connecting CalCal to HMRC for MTD). Submission sends your return to HMRC. First time? Read Sending your first tax return online.
If you see Authentication Failure or Error 1046 on submit, see the authentication failure guide — usually wrong Gateway credentials, inactive SA registration, or wrong UTR.
6. After submission
View submission status, download SA302, or amend if allowed. Submitted years lock against casual edits — amend through the proper amend flow.
Attachments and supporting documents
Some returns need attachments. Add them from the tax year screen before submitting. Keep copies for your records.
Subscription requirements
Submitting SA returns requires a paid plan — not the free trial. Tax-return-only subscriptions include SA without full bookkeeping. See Subscriptions and SA tax return plans.
Further reading
- Understanding Self Assessment
- MTD for Self Assessment (if on MTD)
- Daily Entries (feeds SA sync)
When to contact support
Contact support if submission fails after checking credentials and UTR, if sync figures look wrong versus your books, or if the wrong tax year workflow (MTD vs legacy) appears.
Quick reference
| If you say… | Try this |
|---|---|
| File SA return | Tax → pick year → sync → forms → submit |
| Error 1046 on submit | HMRC authentication failure article |
| Connect to HMRC (import) | Pre-pop in tax year — not same as submit credentials |
| Quarterly updates | You need MTD guide, not this one |
| Blocked on trial | Upgrade subscription |