If you sell a property that isn’t your main home, the tax bill can catch you off guard. Around 300,000 UK landlords file a capital gains tax return each year, and many are surprised by how much they owe. That figure tells me this isn’t a niche issue — it’s something thousands of people deal with annually, often for the first time.
I’ve been writing about property tax for years, and the question I hear most often is simple: “I’m selling a house I used to live in — do I actually have to pay tax on the profit?” The answer depends on timing, reliefs, and a few rules that have changed recently. Here’s what you actually need to know.
If you’re buying a home and plan to sell another property later, it’s worth understanding how ongoing costs like maintenance interact with your tax position. A property lawyer can help you structure the sale to minimise the tax hit.
Capital Gains Tax on Property — The Core Idea
Capital Gains Tax is the tax on the profit you make when you sell or dispose of an asset that has increased in value. For property, it applies when you sell a house that isn’t your main home — a second home, a buy-to-let, or a property you used to live in but now rent out. The key point is that you’re taxed on the gain, not the total sale price.
What I’d do if I were selling a former home: work out the gain first, then check whether Private Residence Relief covers most of it. Many people assume they owe tax when they don’t, or they miss reliefs they’re entitled to.
Why the 60-Day Rule Catches People Out
The biggest change in recent years is the reporting deadline. UK residents must file a return and pay within 60 days of completing the sale. That’s not 60 days from the end of the tax year — it’s 60 calendar days from the day you exchange contracts and hand over the keys. Miss it, and you face a £100 penalty from day 61, with daily and tax-geared penalties stacking up after that.
Consider this scenario: you sell a buy-to-let in March, make a £40,000 gain, and think you’ll sort the tax when you file your Self Assessment in January. By then, you’re already months late. The 60-day return is separate from your annual tax return, though the tax you pay through it is credited against your final bill.
For non-UK residents, the rule is even stricter. You must file a 60-day return for every UK land disposal, regardless of whether any tax is due. That includes commercial property and indirect interests in property-rich companies.
What I notice is that the 60-day window is the single most common reason people end up with penalties. It’s not the calculation that trips them up — it’s the timing. If you’re selling, put the reporting deadline on your calendar the day you agree the sale.
If you’re buying a home and plan to sell your current one, check whether property ladder myths are affecting your timing. A financial advisor can model the tax impact before you commit to a sale date.
Where People Get the Calculation Wrong
Mixing up capital improvements with repairs
This is the most common error I see. HMRC’s PIM2020 guidance draws a clear line: restoring something to its original condition is a revenue expense (deductible against rental income, not CGT), while creating something materially better, larger, or different is a capital improvement (added to your base cost). A new bathroom that’s a like-for-like replacement? Revenue. A new bathroom that adds a shower room where there wasn’t one? Capital. The distinction matters because claiming something as a revenue expense during ownership means you cannot also include it in your CGT base cost — that’s double-counting, and HMRC will flag it.
Forgetting the final nine months rule
Private Residence Relief covers the period you lived in the property as your main home. But even after you move out, the final nine months of ownership always qualify as deemed occupation, provided the property was at some point your main residence. That means if you lived in a house for five years, rented it out for two years, and sold it, the gain for the final nine months of that two-year rental period is still tax-free. Many people miss this and overpay.
Ignoring the spouse transfer opportunity
Transfers between spouses or civil partners are on a no-gain-no-loss basis. The receiving spouse inherits the original base cost, and on a subsequent sale, each spouse is taxed on their share. If one spouse has little or no other income, transferring part of the property before sale can place that portion of the gain in their basic-rate band at 18% instead of 24%. The saving can be substantial — but the transfer must be a genuine change of beneficial ownership, documented before the sale completes.
What I’d do: if you’re married or in a civil partnership and one of you earns significantly less, consider a pre-sale transfer. Each spouse gets their own £3,000 allowance, so a jointly owned property effectively doubles the tax-free amount to £6,000.
→ Scroll right to see all columns
| Cost Type | Treatment | Example |
|---|---|---|
| Purchase price | Capital (base cost) | £220,000 paid for the property |
| SDLT including surcharge | Capital (base cost) | £8,400 stamp duty on purchase |
| Extension adding floorspace | Capital (base cost) | £30,000 loft conversion |
| Like-for-like kitchen replacement | Revenue (not CGT) | £5,000 new units, same layout |
| Roof repair after storm | Revenue (not CGT) | £2,000 fixing damaged tiles |
| Full roof replacement | Capital (base cost) | £8,000 new roof structure |
If you’re reviewing a sale contract, contract review tips can help you spot clauses that affect your tax position. A real estate lawyer can review the sale agreement for any hidden tax implications.
How to Calculate and Pay Your CGT Bill
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Work out your chargeable gain
Start with the sale price. Deduct the costs of selling — estate agent fees, legal fees on the sale. Then deduct the purchase price plus the costs of buying — stamp duty, legal fees, survey costs. Add any capital improvements you’ve made (extensions, new bathrooms that materially exceed the original, full roof replacements). The result is your raw gain. Revenue repairs like fixing a leaky roof do not go into this calculation — they were already deducted against your rental income.
Apply Private Residence Relief
If the property was ever your main home, the gain is time-apportioned. Divide the number of months you lived there (plus the final nine months) by the total months you owned it. That fraction of the gain is tax-free. For example, own a house for 120 months, live in it for 60 months, rent it out for 60 months. The final nine months of ownership qualify, so 69 out of 120 months are exempt — that’s 57.5% of the gain tax-free.
Deduct losses and the annual exempt amount
Subtract any capital losses you’ve made in the same tax year (compulsory), then any brought-forward losses (only down to the £3,000 allowance floor), then the £3,000 annual exempt amount. Jointly owned property can use two allowances — £6,000 total — if you’re married or in a civil partnership.
Apply the correct rate
Stack the remaining gain on top of your other income. The portion that falls within your remaining basic-rate band (up to £37,700 of taxable income after the personal allowance) is taxed at 18%. Anything above that is taxed at 24%. If your other income already uses the full basic-rate band, the entire gain is taxed at 24%.
File and pay within 60 days
Use HMRC’s online service for Capital Gains Tax on UK property. You’ll need the sale completion date, the sale price, the purchase price, and details of any reliefs. Pay the tax at the same time. Late filing penalties start at £100 from day 61, with daily penalties and tax-geared penalties after that. The same disposal is reported again on your Self Assessment tax return, but the tax you’ve already paid is credited against the final bill.
- 1Calculate the raw gainSale price minus purchase price, minus buying and selling costs, plus capital improvements. Revenue repairs are excluded.
- 2Apply Private Residence ReliefTime-apportion the gain based on months lived in the property plus the final nine months of ownership.
- 3Deduct losses and the allowanceSubtract in-year losses, then brought-forward losses (down to £3,000), then the £3,000 annual exempt amount.
- 4Apply the tax rate18% on the portion within your remaining basic-rate band, 24% on the rest. File and pay within 60 days of completion.
If you’re buying a home near a school, school catchment areas can affect property values and your eventual gain. A tenant landlord lawyer can advise if you’re selling a property with tenants in situ.
Frequently Asked Questions
Do I pay CGT if I sell my main home? ▾
What happens if I don’t file the 60-day return? ▾
Can I use my spouse’s allowance? ▾
Does Letting Relief still exist? ▾
What about Furnished Holiday Lets? ▾
Can I deduct mortgage interest from the gain? ▾
A estate lawyer can help if you’re dealing with a property that’s part of an estate or inheritance.
What to Do Next
The most important step is knowing your timeline. The 60-day reporting window starts the day you complete the sale, not the end of the tax year. Calculate your gain early, check whether Private Residence Relief covers most of it, and set aside the tax before you receive the sale proceeds. If you’re married, consider whether a pre-sale transfer to a lower-earning spouse could save you thousands.
If this was useful, you might also want to read Bridging Loans: A Risky UK Home Buying Strategy.
Sources and Further Reading
Top Tips for Buying a House in the UK With Safe Roads in Mind — Practical guidance on location factors that affect property value and resale potential.
Capital Gains Tax on Property: Complete UK Guide. Property Tax Partners, 2026.
Capital Gains Tax UK Property 2026: Complete Guide. UK PropCalc, 2026.
