What does a 'C' prefix tax code on my Welsh payslip mean in 2026/27?

Full answer

The 'C' prefix on your tax code stands for Cymru (Wales). It tells your employer's payroll that HMRC has identified you as a Welsh taxpayer, normally because your main residence is in Wales, regardless of where you work. So a code like C1257L applies the standard £12,570 Personal Allowance with Welsh rates, while CBR, CD0 or CK codes are the Welsh equivalents of BR, D0 and K codes. The letter does not change how much tax you pay by itself; it simply directs your income tax to the Welsh Government rather than to the UK Exchequer or Holyrood. Under devolution, the UK Government sets each band threshold and then reduces the main UK rates by 10p, allowing the Senedd to add its own Welsh Rates of Income Tax (WRIT). For 2026/27 Wales has set each rate at 10p, so the combined rates remain the same as England and Northern Ireland: 20% basic, 40% higher and 45% additional. With a C-prefixed code and a £12,570 allowance you pay 20% on income between £12,570 and £50,270, 40% up to £125,140, and 45% above that. National Insurance (employee 8% then 2%) and the Personal Allowance taper above £100,000 are UK-wide and unaffected by the C prefix. This is the key difference from Scotland: a Scottish 'S' code genuinely changes your bill because Scotland has its own bands and rates (including 21%, 42%, 45% and 48%). A Welsh 'C' code, by contrast, produces an identical result to a non-prefixed code for now. If you have moved into or out of Wales, tell HMRC so your code is corrected; an outdated C prefix won't cost you money in 2026/27, but keeping your address current ensures the right nation receives your tax and your code stays accurate if rates ever diverge.

Try the calculator