If your tax code starts with an S or a C, the prefix tells your employer which set of Income Tax rates to use, not how much allowance you get. S means Scottish Income Tax; C means Welsh (Cymru) Income Tax. England and Northern Ireland have no prefix.
This is part of our UK tax codes explained series.
What do the S and C prefixes mean?
The prefix sits in front of the rest of your code: S1257L is the Scottish version of the standard 1257L code, and C1257L is the Welsh version. The £12,570 Personal Allowance is UK-wide and applies the same way, so the number and letter still mean exactly what they do without the prefix. What changes is the rates and bands applied to your taxable income:
- S, your Income Tax is set by the Scottish Parliament, which has its own set of rate bands.
- C, your Income Tax is set under the Welsh rates of Income Tax.
You can have any of the usual letters and prefixes combined, for example SBR (Scottish basic rate on a second job) or SD0 (Scottish higher rate). The prefix simply layers the right rate table on top.
Who gets an S or C tax code?
Your prefix is decided by where you live, not where you work or where your employer is based. HMRC works out your "main residence" from the address it holds for you:
- Live in Scotland → S prefix, Scottish Income Tax.
- Live in Wales → C prefix, Welsh Income Tax.
- Live in England or Northern Ireland → no prefix.
This is why keeping your address up to date with HMRC matters, if you move across the border and HMRC's records are stale, you can end up on the wrong rates.
What to do if the code is wrong
If you think your tax code is wrong, do not just wait, an incorrect code is corrected from the date HMRC updates it, and any over- or under-payment is squared up afterwards. Steps to take:
- Check your latest tax code notice (the "PAYE Coding Notice", form P2) in your HMRC personal tax account. It shows how the code was built up.
- Compare it to your real situation, one job or several, any benefits in kind, untaxed income, or earlier-year underpayments being collected.
- Check the prefix matches where you live, an S when you live in England (or no prefix when you live in Scotland) usually means HMRC has the wrong address.
- Update your address with HMRC if you have moved nation, that is what drives the prefix.
- Tell HMRC if anything is out of date, online, via the HMRC app, or by phone. They will issue a revised code to your employer.
- Watch your next payslip to confirm the new code has been applied and any refund has come through.
Frequently asked questions
Why does my tax code start with S?
Because HMRC has you down as living in Scotland, so you pay Scottish Income Tax. The S prefix just selects the Scottish rate bands; your £12,570 allowance is unchanged.
What does a C tax code mean?
The C prefix means you are a Welsh taxpayer and pay the Welsh rates of Income Tax. C1257L is the Welsh version of the standard 1257L code.
I moved to England but still have an S code, what do I do?
Tell HMRC your new address. Your prefix follows your main residence, so once the records are updated HMRC will issue a code without the S prefix.
Think your tax code is wrong? It is one of the most common payroll errors, and HMRC will not always spot it for you. Zmartly's Self Assessment and personal tax team can check your code against your circumstances and deal with HMRC on your behalf. Get in touch for a free review, or book a free Tax Health Check.
