Selling a buy-to-let flat, offloading shares after a strong run, or cashing out a crypto portfolio you have held for years? Each of those events could leave you with a Capital Gains Tax bill, and HMRC expects you to report it correctly and on time. The good news is that not every disposal needs an accountant.
Some CGT calculations are straightforward enough to handle yourself. Others, particularly those involving property, mixed-use assets, or overlapping reliefs, are where mistakes get expensive.
This guide walks through how CGT works in the UK right now, current rates and allowances, reporting deadlines you cannot afford to miss, and the specific situations where bringing in a qualified accountant saves you more than it costs.
What Triggers Capital Gains Tax
Capital Gains Tax applies when you dispose of an asset that has increased in value since you acquired it. The word “dispose” is broader than most people expect. It covers selling an asset for cash, giving it away as a gift, swapping it for something else, or receiving compensation when an asset is lost or destroyed. HMRC does not tax the full sale price. CGT is charged only on the gain, minus any allowable costs such as legal fees, stamp duty, or improvement costs.
The most common assets that attract CGT include second homes and buy-to-let properties, shares and securities held outside an ISA or pension, cryptocurrency tokens, personal possessions valued above £6,000, and business assets such as premises or goodwill.
Your main residence is normally exempt thanks to Private Residence Relief, though partial charges can apply if you have let the property or used part of it exclusively for business.
Current CGT Rates and Allowances for 2025/26
Following the Autumn Budget 2024, the government aligned CGT rates across most asset types. For 2025/26, basic rate taxpayers pay 18% on chargeable gains while higher and additional rate taxpayers pay 24%.
These rates now apply to both property and other chargeable assets, removing the previous split. You can check the full breakdown of current CGT rates and annual exempt amounts on GOV.UK.
Every individual receives an Annual Exempt Amount of £3,000 for the 2025/26 tax year, the amount of gain you can make before CGT becomes payable. This has fallen sharply from £12,300 in 2022/23, which means many more people now find themselves above the threshold. For trustees, the exempt amount is £1,500.
Business Asset Disposal Relief (formerly Entrepreneurs’ Relief) operates at 14% for qualifying disposals from April 2025, rising to 18% from April 2026, with a £1 million lifetime limit. If you are selling a business or shares in a qualifying trading company, this relief makes a significant difference, but the calculations are more involved than a standard disposal.
Reporting Deadlines That Catch People Out
CGT reporting deadlines depend on the type of asset you have sold, and this is where many people come unstuck.
UK Residential Property: The 60-Day Rule
If you sell UK residential property on which CGT is due, you must report the disposal and pay the estimated tax within 60 days of the completion date. This is reported through HMRC’s Capital Gains Tax on UK property account, which is separate from your Self Assessment. The 60-day clock starts from the date of completion, not the date of exchange, and late reporting triggers automatic penalties plus interest on any unpaid tax.
The rule applies regardless of whether you already file a Self Assessment return. Even if you plan to include the gain on your annual tax return later, HMRC still requires the separate 60-day report. If the disposal results in no CGT liability because reliefs or losses cover the full gain, you do not need to file the 60-day return.
All Other Assets: Self Assessment
For shares, crypto, personal possessions, and other non-property assets, CGT is reported through your Self Assessment tax return. The deadline for online filing and payment is 31 January following the end of the tax year. So for gains made between 6 April 2025 and 5 April 2026, the reporting and payment deadline is 31 January 2027.
You need to complete the Capital Gains Summary pages of your return if your total gains (before deducting losses) exceed the £3,000 annual exempt amount, or if your total disposal proceeds exceed £50,000 in the year, even if no tax is due. If you do not currently file Self Assessment but have made taxable gains, you will need to register with HMRC.
When You Can Handle CGT Yourself
There are genuine scenarios where CGT reporting is simple enough to manage without professional help. If you have sold a small number of shares through a single trading platform, your provider will usually give you the acquisition cost and disposal proceeds. Deduct your £3,000 annual exempt amount, apply the correct rate based on your income tax band, and report it through Self Assessment.
Similarly, if you are selling a personal possession such as a piece of jewellery or an antique for under £6,000, CGT does not apply at all. If the item sells for more than £6,000, the gain is calculated under the chattels rules, which cap the chargeable gain at five-thirds of the excess over £6,000.
For a single item with clear purchase and sale records, this is a manageable calculation. HMRC also provides free online calculators for straightforward property disposals where the ownership history is uncomplicated.
When Professional Help Pays for Itself
The situations below are where CGT calculations become layered, where reliefs interact, deadlines are tight, and where getting it wrong means overpaying tax or facing penalties. In each case, an experienced capital gains tax accountant can identify savings that more than cover their fee.
Property Disposals
Property sales are the most common trigger for complex CGT calculations. If you have owned a rental property for many years, you may need to account for periods of residence versus letting, calculate letting relief, and determine which improvement costs qualify as allowable deductions.
Properties that changed use during ownership, for example a home that was later rented out, require careful apportionment of the gain between exempt and chargeable periods.
The 60-day reporting window makes professional support especially valuable. You need accurate figures within two months of completion, and underestimating the liability leads to interest charges while overestimating ties up cash until HMRC processes your Self Assessment.
Share Portfolios and Multiple Disposals
Selling shares is not always as simple as comparing the buy and sell price. If you have bought the same shares at different times and prices, HMRC requires you to use share matching rules: the same-day rule, the bed-and-breakfast rule (matching with purchases within 30 days), and the Section 104 pooling rule. These determine which acquisition cost is used against each disposal, and mistakes here are one of the most frequent errors HMRC picks up on.
Employee share schemes such as EMI, CSOP, or SAYE options add another layer. The tax treatment varies depending on the scheme type, the exercise price, and how long shares were held after exercise, and an accountant familiar with share-based remuneration can ensure the right base cost is used.
Cryptocurrency
Crypto assets sit firmly within CGT for individual holders, and HMRC has made clear that all disposals must be reported. That includes selling tokens for pounds, swapping one cryptocurrency for another, spending tokens on goods or services, and gifting crypto to someone other than your spouse. Each transaction is a separate disposal, and for active traders the volume of calculations can be substantial.
The challenge with crypto is record-keeping. Many people traded across multiple wallets and exchanges over several years without tracking the sterling value at each transaction.
Reconstructing this history, applying HMRC’s pooling rules for crypto assets, and identifying allowable losses requires patience and expertise. If you have significant crypto tax obligations, working with an accountant who understands digital assets will help you report correctly and claim every loss you are entitled to.
Business Asset Disposals
Selling a business, or shares in a personal trading company, introduces some of the most valuable reliefs available. Business Asset Disposal Relief can reduce the effective CGT rate to 14% on up to £1 million of qualifying lifetime gains.
But eligibility is strict. You must have owned the business or held at least 5% of shares and voting rights for a minimum of two years, and the company must be a trading company rather than an investment company.
Getting the qualifying conditions wrong means losing access to the relief entirely. For partnerships, sole traders selling goodwill, or directors disposing of shares, professional advice ensures the disposal is structured to maximise available reliefs and that any rollover or holdover relief is properly claimed.
Common CGT Mistakes and How to Avoid Them
Even straightforward disposals can go wrong if you overlook the basics. These are the errors we see most often, and each one is avoidable with a bit of planning.
- Not reporting a disposal at all. HMRC receives data from Land Registry, share registrars, and increasingly from crypto exchanges. If a disposal appears in their records but not on your tax return, expect a letter and potentially a penalty.
- Forgetting to deduct allowable costs. Legal fees, estate agent commissions, stamp duty on purchase, and genuine improvement costs (not repairs) can all reduce the chargeable gain. Many people leave money on the table simply by not claiming what they are entitled to.
- Overlooking capital losses. If you made a loss on a previous disposal, you can carry it forward indefinitely and set it against future gains, but only if the loss was reported to HMRC in the year it occurred or within four years.
- Missing spousal transfer opportunities. Transfers between married couples and civil partners take place at no gain and no loss, so you can shift an asset to the partner with the lower income tax rate or unused annual exempt amount before disposing of it. This is entirely legal and well established, but the transfer must happen before the sale completes.
Most of these mistakes stem from not knowing the rules exist rather than deliberate avoidance, which is exactly why a quick review with an accountant before you dispose of an asset can save you from costly surprises.
How an Accountant Approaches Your CGT Position
A qualified accountant does more than fill in the numbers. They review your full tax position for the year, including income, existing losses, and reliefs you may be entitled to claim. This holistic view often uncovers savings that a standalone CGT calculation would miss.
For property disposals, they will confirm the correct base cost (particularly important for inherited property), identify all allowable expenditure, apply the correct apportionment for Private Residence Relief and letting relief, and prepare the 60-day return with accurate estimated figures. For share and crypto disposals, they will apply the correct matching rules, reconcile transaction histories, and ensure losses are properly reported and carried forward.
Timing advice is another area where accountants add value. Splitting disposals across two tax years to use two annual exempt amounts, crystallising losses before a sale, or deferring a disposal to fall within a lower income year are all legitimate strategies that require forward planning.
Get Your CGT Right the First Time
Whether you are selling a property, disposing of shares, or sorting out years of crypto transactions, eAccounts can handle your CGT calculations, reporting, and payment to HMRC accurately and on time. Our chartered accountants work with individuals, sole traders, and company directors across the UK, with fully online service so you get expert support without visiting an office.
If you have a disposal coming up or a deadline approaching, get an instant quote, speak to one of our accountants near you, or call us on 029 2105 5592 today.
FAQs
Do I need to pay Capital Gains Tax on my main home?
In most cases, no. Your main residence is usually exempt from CGT thanks to Private Residence Relief. However, partial charges can apply if you let the property out, used part of it exclusively for business, or were absent for extended periods during ownership.
How much can I gain before I owe CGT?
For the 2025/26 tax year, the Annual Exempt Amount is £3,000 per individual. You only pay CGT on gains above this threshold. If your total gains for the year fall below £3,000, there is no tax to pay, though you may still need to report if your disposal proceeds exceed £50,000.
What happens if I miss the 60-day property reporting deadline?
HMRC will issue a late filing penalty, starting at £100 if filed within three months of the deadline. Further penalties and interest on unpaid tax accumulate the longer you leave it. Even if you intend to include the gain on your Self Assessment later, the 60-day report is a separate obligation.
Can I reduce my CGT bill by splitting a sale across two tax years?
Yes, in certain situations. If you are disposing of multiple assets, selling some before 5 April and the rest after can allow you to use two annual exempt amounts. This is a legitimate and commonly used planning strategy, though it needs to be arranged before the disposals take place.
Do I need a specialist accountant for CGT or will any accountant do?
Any qualified accountant can handle basic CGT reporting, but complex scenarios involving property apportionments, share matching rules, crypto transaction histories, or Business Asset Disposal Relief benefit from someone with specific CGT experience. A specialist is more likely to identify reliefs and deductions that reduce your final bill.
