The 60-day CGT return is a standalone filing that must be completed promptly after a property sale. It is widely understood as the immediate obligation. What is less well understood is the relationship between the 60-day return and the annual Self Assessment tax return — and whether the property sale affects whether you need to file a Self Assessment at all.
The 60-day return and Self Assessment are separate obligations
The 60-day property return (filed via HMRC's UK Property Reporting Service) is a provisional return. It captures the gain, applies an estimate of your income and tax position for the year, and produces a payment on account. That payment reduces the CGT liability but does not finalise it.
If you are required to file a Self Assessment tax return, you must also include the property sale on the capital gains pages (SA108) of that return. The annual return is where the gain is definitively reported, where any corrections to the estimates in the 60-day return are made, and where any over or underpayment is settled.
Who needs to file Self Assessment?
You are required to be in Self Assessment and file a return if any of the following apply in the tax year:
- You are self-employed with trading income above £1,000
- You have rental income (even from a different property)
- Your income exceeds £100,000 (even if PAYE)
- You have foreign income
- You have taxable untaxed income above £2,500
Importantly, HMRC may also require a Self Assessment return simply because you made a capital gain — particularly if the gain is significant or if HMRC has received information about the disposal (for example, from Land Registry data). If HMRC issues a notice to file, you must file even if you are not otherwise in Self Assessment.
What if I am not in Self Assessment and have no other income?
If you are not in Self Assessment and your only reportable event in the tax year is the property sale, the 60-day return is sufficient — provided:
- The gain has been correctly calculated
- The 60-day payment covered the full CGT liability
- You have no other untaxed income that needs reporting
However, if HMRC subsequently issues a Self Assessment notice for the year in question, you will need to file one. It is good practice to keep records of the 60-day filing for at least five years.
How the 60-day payment is reconciled in Self Assessment
The amount paid via the 60-day return is a payment on account against your overall tax bill for the year. When you complete your Self Assessment return, the CGT figure is recalculated using the actual income figures for the full year (not estimates). The 60-day payment is credited.
If the final CGT bill is higher than the 60-day payment (for example, because your income was higher than estimated, pushing more of the gain into the 24% band), there is a balancing payment due by 31 January following the end of the tax year.
If the final CGT bill is lower (for example, because you made pension contributions after filing the 60-day return, or because investment losses were crystallised later in the year), HMRC will credit the overpayment against other liabilities or refund it.
The deadline difference
The 60-day return deadline is 60 days from completion of the property sale. The Self Assessment return deadline is:
- 31 October (paper) or 31 January (online) following the end of the tax year
For a property completing in June 2026 (in the 2026/27 tax year), the 60-day return is due in August 2026. The Self Assessment return for 2026/27 is not due until 31 January 2028.
What happens if I do not file Self Assessment when I should?
Late filing penalties apply to Self Assessment returns separately from the 60-day CGT return penalties. If you do not register for Self Assessment when required, HMRC can charge penalties and interest on any underpayment that the annual return would have captured.
It is worth checking your filing obligations at the start of each tax year in which you sell a property. If you become newly required to file Self Assessment because of the property sale, register with HMRC promptly.
Working through both filings together
Managing both the 60-day return and Self Assessment in the same year — particularly if you also have rental income, employment income, or investments — can be complex. A Chartered Accountant/Chartered Tax Advisor can handle both filings, ensure the 60-day provisional return is consistent with the final Self Assessment position, and identify if any correction or refund is due.