Personal tax & Self Assessment
Last reviewed 20 July 2026
Self Assessment is how HMRC collects tax that isn’t taken automatically through a payroll. If you have income that arrives untaxed, this is your system — like it or not.
Who normally needs to file
- Sole traders and partners
- Company directors taking dividends
- Landlords with rental income
- Higher earners with investment income, or income over £150,000
- Anyone HMRC has sent a notice to file
If you’re new to any of these, you must register by 5 October after the end of the tax year in which the income started.
The deadlines
| What | When |
|---|---|
| Register for Self Assessment | 5 October |
| Paper return | 31 October |
| Online return | 31 January |
| Pay your tax (and first payment on account) | 31 January |
| Second payment on account | 31 July |
Miss 31 January and there’s an automatic £100 penalty — even if you owe nothing.
Payments on account, demystified
If your last bill was over £1,000 (and mostly untaxed at source), HMRC asks for next year’s tax in advance: half on 31 January, half on 31 July, each based on last year’s bill. The first year this happens, you effectively pay one and a half years of tax at once — the cash-flow surprise that catches almost every new sole trader. We flag it months ahead so it never ambushes you.
Scottish taxpayers, take note
If you live in Scotland, your wages, profits, and rental income are taxed at Scottish rates and bands — six of them in 2026/27, from 19% to 48% — while savings and dividend income still use UK-wide rates. Software gets this right; casual arithmetic often doesn’t.
Making Tax Digital changes the rhythm
From April 2026, sole traders and landlords with qualifying income over £50,000 keep digital records and send quarterly updates instead of one annual return — with the threshold dropping to £30,000 in April 2027 and £20,000 in April 2028. See our blog for the latest on MTD, and note that MTD work is priced separately in your personalised quote.
How we help
We prepare and file your return, tell you exactly what to pay and when, and look for the planning opportunities a form-filling service never will — pension timing, dividend planning, capital gains, and inheritance tax down the line.
This guide is a general summary, not advice for your specific circumstances. Rules and rates change — for a recommendation you can act on, talk to us.