Tax After Divorce in the UK: HMRC, Marriage Allowance, and Capital Gains

Divorce changes your tax position in ways that are not immediately obvious. If you do not notify HMRC, you could end up with the wrong tax code, an unexpected bill for Marriage Allowance overpayment, or a Capital Gains Tax liability on assets you thought were exempt.

Here is what needs updating and the order that matters.

Cancel the Marriage Allowance

If either spouse was transferring £1,260 of their Personal Allowance to the other under the Marriage Allowance, this must be cancelled as soon as the divorce is finalised. The allowance is only available to married couples and civil partners.

Who needs to act: Either spouse can cancel it through their personal tax account on GOV.UK or by calling HMRC once the relationship has ended.

What happens if you do not cancel: HMRC will continue applying the old tax codes. The higher earner keeps receiving the benefit, and the lower earner keeps losing part of their Personal Allowance. When HMRC eventually catches up, you may face an underpayment notice.

If your relationship has ended, HMRC may backdate the change to the start of the tax year (6 April). So if your Final Order is granted in January 2027, the change may be backdated to 6 April 2026.

Update Your Tax Code

Notify HMRC of your change in marital status through your personal tax account or by calling the Income Tax helpline. HMRC will issue a new tax code to your employer. Key changes:

• Your Personal Allowance reverts to the standard individual allowance
• Any adjustments for Marriage Allowance are removed
• If your address has changed, update it — HMRC correspondence goes to the address on file

Capital Gains Tax on Asset Transfers

Transfers of property, shares, or business assets between spouses are normally CGT-free (the "no gain, no loss" rule). After separation, that treatment continues within a limited period, and there is no time limit for transfers made under a formal court order or written divorce agreement.

Under current rules, separating spouses generally have until the end of the third tax year after the tax year of separation to transfer assets on a "no gain, no loss" basis. There is no time limit where the transfer is made in accordance with a formal court order or written divorce agreement.

If neither route applies and the ordinary window has closed, a transfer may be treated as a disposal at market value, potentially triggering a significant CGT bill. Transfers under a sealed Consent Order or Financial Remedy Order remain within the no-gain-no-loss treatment even after the ordinary three-tax-year window. Get the transfer documented under the applicable route — do not let it lapse.

Stamp Duty and Land Transaction Tax

In England: Transfers of property under a qualifying divorce agreement or court order are exempt from Stamp Duty Land Tax (SDLT), and there is no need to tell HMRC about the transfer.

In Wales: SDLT does not apply. Wales has its own Land Transaction Tax (LTT), administered by the Welsh Revenue Authority. A qualifying transfer between former spouses or civil partners under a qualifying court order or agreement is exempt from LTT, no LTT return is required, and the exemption does not cover a transfer to a third party. If a return is required for a non-qualifying Welsh transaction, it is due within 30 calendar days of the day after the effective date.

Council Tax Single-Person Discount

If you are now living alone (or only with children under 18), you qualify for a 25% single-occupancy Council Tax discount. In Wales, apply to your local council — Cardiff, Swansea, Newport, Wrexham, or whichever Welsh authority covers your address.

The discount should apply from the date you became the sole adult occupant, although your council may ask for evidence and its backdating process may differ. Apply as soon as your ex-spouse moves out to avoid paying full Council Tax unnecessarily.

Council Tax Reduction Scheme (Wales-Specific)

Wales operates its own Council Tax Reduction Scheme (replacing the old Council Tax Benefit). If your household income has dropped significantly after divorce, you may qualify for a further reduction beyond the 25% single-person discount. Eligibility is based on income, savings, and household composition. Apply through your local Welsh council.

What to Do First

1. Cancel the Marriage Allowance (if applicable)
2. Update your personal tax account with your new name and address
3. Check your tax code is correct on your next payslip
4. File any SDLT/LTT returns required for property transfers. A qualifying Welsh divorce transfer is non-notifiable; any required Welsh return is due within 30 calendar days of the day after the effective date.
5. Apply for the Council Tax single-person discount

The Wales Post-Divorce Checklist includes an HMRC update checklist covering every notification you need to make, plus a Council Tax application template for Welsh local authorities.

See more Wales guides →