CD0 is the Welsh equivalent of the D0 code. It applies 40% to all income from this source with no personal allowance — used for second jobs when main income is already in the higher rate band.
Forty per cent on every pound. That is what the CD0 tax code means for Welsh taxpayers. No Personal Allowance, no basic rate band, no graduated scale. CD0 is the Welsh equivalent of the D0 tax code used in England and Northern Ireland. HMRC assigns it when your combined income from all sources exceeds the basic rate threshold (£50,270 in 2025/26) and your allowance has already been allocated to your main income source. The C prefix confirms your residence in Wales.
CD0 is correct when your total income from all sources pushes you into the higher rate band and the income from this particular source falls entirely within that band. The most common scenarios are:
Second job for a higher rate Welsh taxpayer. Your main job pays £55,000 with a C1257L code (your full Personal Allowance with the Welsh prefix). You take a second job paying £15,000. Since your main job already uses your allowance and basic rate band, every pound from the second job is taxed at the Welsh higher rate of 40%. HMRC assigns CD0 to the second employer.
Second pension for a Welsh retiree. Retired individuals often have multiple pension sources: a state pension, an occupational pension, and perhaps a personal pension. HMRC allocates the Personal Allowance to one pension and assigns CD0 to any others where the total income exceeds £50,270.
Company directors living in Wales with multiple directorships. If you direct two companies and draw salary from both, the second directorship salary may carry a CD0 code when your combined income exceeds the basic rate threshold.
Both CD0 and CBR are flat-rate Welsh codes with no Personal Allowance, but they apply at different rates.
| Feature | CBR | CD0 |
|---|---|---|
| Tax rate applied | 20% (Welsh basic rate) | 40% (Welsh higher rate) |
| Personal Allowance | None | None |
| Typical scenario | Second job, total income under £50,270 | Second job, total income over £50,270 |
| Who gets it | Welsh basic rate taxpayers with a second income | Welsh higher rate taxpayers with a second income |
| Risk of overpayment | Lower (20% is often too much if you have unused allowance) | Higher (40% on every pound is steep if your total income is near the threshold) |
The critical distinction: If your total income from all sources is below £50,270, HMRC should assign CBR (not CD0) to your second income. If your total income exceeds £50,270 but your second income partly falls within the basic rate band, CD0 may be overtaxing you. In that case, HMRC should split the coding rather than applying a flat 40%.
Gareth earns £52,000 from his main employment and £8,000 from weekend consultancy work. He lives in Swansea, so all his codes carry the Welsh C prefix. His total income is £60,000.
Main job (C1257L code):
| Item | Amount |
|---|---|
| Gross salary | £52,000 |
| Personal Allowance | £12,570 |
| Taxable at 20% (£12,571-£50,270) | £37,700 x 20% = £7,540 |
| Taxable at 40% (£50,271-£52,000) | £1,730 x 40% = £692 |
| Total tax on main job | £8,232 |
Second job (CD0 code):
| Item | Amount |
|---|---|
| Gross consultancy income | £8,000 |
| Tax at 40% (all of it) | £8,000 x 40% = £3,200 |
Total tax across both jobs: £8,232 + £3,200 = £11,432
This is correct because Gareth's entire second income falls above the £50,270 threshold. Every pound of consultancy income genuinely belongs in the Welsh higher rate band.
Important: Gareth pays exactly the same amount of tax as someone in England with D0 on their second job. The C prefix changes the administrative classification but not the amount, because Welsh and English rates are identical for 2025/26.
CD0 can be incorrect in several situations, and the result is always the same: you pay too much tax through PAYE and need to reclaim the difference.
Your total income is below £50,270. If your main job pays £40,000 and your second job pays £8,000, your total is £48,000. All of this falls within the basic rate band. Your second job should be coded CBR (20%), not CD0 (40%). The difference on £8,000 is £1,600 per year in overpaid tax.
Your Personal Allowance is not fully used. If you started a new main job mid-year and did not provide a P45, HMRC may have assigned C1257L to your old employer and CD0 to your new one. Your allowance should transfer to the new job.
You have stopped your main job. If you leave your primary employment but keep the second job, that job should now receive your Personal Allowance. HMRC may not update the code automatically.
Your income has dropped. A pay cut, reduced hours, or redundancy at your main job could mean your total income no longer reaches the higher rate threshold. CD0 would then be incorrect.
You have moved out of Wales. If you no longer live in Wales, the C prefix itself is wrong. Your code should be D0, not CD0. While the tax rate is the same today, HMRC's records should reflect your correct taxpayer status.
If CD0 is incorrect, you are losing money with every payslip. Act quickly.
Option 1: Update online. Sign in to your Personal Tax Account on gov.uk. Navigate to "Check your Income Tax" and update your estimated income for the year. HMRC will recalculate and issue a revised code to your employer, usually within 2-4 weeks.
Option 2: Call HMRC. Phone the income tax helpline on 0300 200 3300 (Monday to Friday, 8am to 6pm). Explain your income sources and ask them to review your coding. Have your NI number and employer PAYE references ready.
Option 3: Wait for the P800 reconciliation. At the end of the tax year, HMRC automatically reconciles your PAYE records. If you overpaid, they issue a P800 tax calculation showing the refund due. This can take until October or November after the tax year ends, so you may wait up to 18 months. Calling or updating online is faster.
Retirees living in Wales are among the most common CD0 recipients, and the coding can be confusing when multiple pension sources are involved.
The State Pension is taxable but paid gross (no tax deducted at source). HMRC accounts for it by reducing the Personal Allowance available to your other pension sources. If the State Pension in 2025/26 is £11,502 (full new State Pension), HMRC reduces your occupational pension allowance to £12,570 minus £11,502 = £1,068. Your occupational pension would then receive a code like C106L.
If you also have a personal pension on top of both, that third source may receive CD0 if your total pension income exceeds £50,270.
| Pension source | Typical code | Tax treatment |
|---|---|---|
| State Pension | No code (paid gross) | Taxable, accounted for via other codes |
| Occupational pension (primary) | Adjusted CL code (e.g. C106L) | Allowance minus State Pension allocation |
| Personal pension (secondary) | CD0 | 40% on all income if total exceeds £50,270 |
If you have been on CD0 incorrectly for part or all of the tax year, you can reclaim the overpayment.
In-year correction. Update your income estimate on your Personal Tax Account. HMRC issues a new code that compensates for the overpayment already made by giving you a larger allowance for the remainder of the year.
After the tax year. HMRC sends a P800 calculation. If it shows a refund, you can claim online and receive payment within 5-10 working days by bank transfer. If HMRC does not send a P800 (they sometimes miss cases with multiple employers), you can call to request a manual review.
Via Self Assessment. If you file a Self Assessment return (because you have self-employment income, rental income, or income over £150,000), any PAYE overpayment is automatically reconciled through your return. The overpaid amount reduces your Self Assessment liability or generates a refund.
Related tax codes: Welsh tax codes | CBR tax code | CD1 tax code | D0 tax code
TapTax connects to your bank, categorises expenses automatically, and submits quarterly updates to HMRC. Free plan, no card required.
