Of all the deadlines in personal tax, this is the one we see missed most often. Not because it is complicated, but because it does not behave like any of the others.
Sixty days, from completion
Dispose of a UK residential property at a gain and you have 60 days from completion to report it and pay the tax. Not from exchange. Not from the end of the tax year. From the day the sale completes and the money moves.
It is a separate filing from your tax return, and it comes long before it. Someone selling a rental in June has a filing obligation in August, at a point when they are not thinking about tax at all and their accountant may not even know the sale happened.
The disposal is then picked up again on your self assessment at the year end. So it is reported twice, which is a further source of confusion.
Why it gets missed
Three reasons, in our experience.
The solicitor handles the conveyancing and the client reasonably assumes the tax side is covered somewhere in that process. It is not.
The sale happens mid-year, and the client's habit is to tell us about their affairs in one go, after 5 April. By then the window has closed.
And the gain is often assumed to be smaller than it is. A property held for fifteen years has a base cost that feels recent and is not.
The penalties are entirely self-inflicted
Late filing brings automatic penalties, and interest runs on tax paid late. None of it is discretionary and none of it depends on whether the gain was calculated correctly. You can do everything right on the numbers and still pay for being late.
Which is the frustrating part: this is a deadline where being organised is worth actual money, and being disorganised costs you a sum you cannot argue down.
What to do before you sell
Tell us before you exchange, not after you complete. That single change turns a scramble into an administrative task.
With notice we can model the gain and the available reliefs, look at which tax year it is better to complete in, and check whether anything about the ownership structure should change first. Once contracts are exchanged, most of those options have gone.
We also need the boring paperwork: what you paid, when, what you spent on improvements as opposed to repairs, and the dates of any period it was your main residence. Improvements come off the gain; repairs do not. People routinely have the receipts and do not realise they matter.
The sequence, plainly
Before marketing: model the gain, the reliefs, and the timing.
On completion: the 60-day reporting and payment window opens, and we file inside it.
At the year end: the disposal is picked up again on your self assessment.
One more thing
This applies to UK residential property disposed of at a gain. If you are selling at a loss, or the property has been your only home throughout, the position is different. It is still worth a conversation rather than an assumption, though, because "throughout" does a lot of work in that sentence.
If you are even thinking about a disposal, a ten-minute call now is worth more than any amount of tidying up afterwards.
Common questions
Does the 60 days run from exchange or completion?
Completion. Exchange is when you are legally committed, but the clock starts on the day the sale completes and the money moves. People who diarise from exchange give themselves a shorter window than they think.
Do I need to report if I am selling my own home?
Generally not, where private residence relief covers the whole gain. The word doing the work is "whole". If you let it out for a period, used part of it exclusively for business, or the grounds are large, relief may be partial and a reporting obligation can arise.
What if I sell at a loss?
There is no 60-day return where there is no tax to pay. The loss should still be reported on your self assessment so it is available to set against future gains.
Does this apply to commercial property or shares?
No. The 60-day regime is specific to UK residential property. Gains on commercial property, shares and other assets are reported through self assessment in the normal way.
What counts as an improvement rather than a repair?
Broadly, improvements enhance the property beyond its original state and come off the gain: an extension, a new conservatory, or central heating installed for the first time. Repairs restore what was there and do not. A replacement kitchen is often argued either way and depends on the facts, which is exactly why the receipts matter.
I have already missed the deadline. What now?
File as soon as you can. Penalties and interest accrue with time, so the position gets worse the longer it is left, and there is no version of this where waiting helps. Tell us and we will get it filed.
