Tax code · 2026/27

C0T means you get no tax-free personal allowance

Tax code C0T gives you no tax-free personal allowance for the 2026/27 tax year. Every pound you earn from this job or pension is taxed, starting at the basic rate and moving up through the bands as your earnings rise. It usually means HMRC has no record of your income details, so it is worth checking.

What does each part of C0T mean?

0T is often used when you start a new job without a P45 and have not completed a starter checklist, or when your allowance has been used up elsewhere.
If this is your only job and you earn under £12,570 a year, you are probably overpaying tax. Ask HMRC to review it.
Unlike BR, 0T uses the full set of bands rather than one flat rate, so higher earners pay higher rate tax on the relevant portion.
The C prefix means you are a Welsh taxpayer. Welsh rates are currently the same as those in England and Northern Ireland.

How much tax do you pay with code C0T?

The table shows income tax and take-home pay in 2026/27 for four salaries with code C0T, compared with the standard code 1257L. National Insurance is not affected by your tax code.

Salary	Tax with C0T	Tax on standard code	Take-home with C0T	Per month
£25,000	£5,000	£2,486	£19,006	£1,584
£35,000	£7,000	£4,486	£26,206	£2,184
£50,000	£12,460	£7,486	£34,546	£2,879
£75,000	£22,460	£17,432	£49,029	£4,086

On £35,000 the effective rate with C0T is 25.1%, against 17.9% on the standard code, a difference of £2,514 a year. Use the take-home pay calculator with your own salary, pension and student loan.

Frequently asked questions

Is tax code C0T correct for me?

Compare C0T with the standard code 1257L. The difference should match an adjustment you recognise, such as a company benefit, job expenses, Marriage Allowance or an underpayment from an earlier year. If it does not, ask HMRC to review it.

How much tax do I pay on £35,000 with tax code C0T?

On £35,000 with code C0T income tax is £7,000 a year in 2026/27, leaving take-home pay of £26,206 (£2,184 a month) after National Insurance of £1,794. On the standard code it would be £4,486.

How do I change tax code C0T?

You cannot change it yourself; only HMRC can issue a new code. Update your details in your HMRC Personal Tax Account or call 0300 200 3300 with your National Insurance number and details of your income and benefits. HMRC sends the new code to your employer and any tax overpaid in the year is refunded through your pay.

What does the C prefix mean?

The C prefix means HMRC has recorded your main home as being in Wales. The Welsh Government sets Welsh rates, which are currently the same as England's, so the code makes no difference to your tax today.