Capital Gains Tax Accountant: When You Need One and What They Actually Do

Selling something that’s grown in value — a second property, a share portfolio, a business you’ve built — should feel like a win. For a lot of people, though, it comes with an unwelcome surprise: a Capital Gains Tax bill that’s larger than expected, or a strict reporting deadline they didn’t know existed until it had already passed. With the tax-free allowance shrinking sharply in recent years and property sales now facing a genuinely tight reporting window, getting this wrong has become easier than most people realise.

This guide explains exactly what a capital gains tax accountant does, the situations where getting one involved genuinely matters, the rates and deadlines currently in force, and what the service tends to cost. It reflects how we handle CGT work directly for property investors, shareholders, and business owners.

Quick Answer

A capital gains tax accountant calculates what you owe when you sell or dispose of an asset that’s increased in value — property, shares, crypto, or a business — and makes sure it’s reported to HMRC correctly and on time. For UK property, that means a strict 60-day reporting and payment window from completion; for most other assets, it’s handled through your Self Assessment return by 31 January. With the tax-free Annual Exempt Amount now down to just £3,000, far more people fall within CGT’s reach than a few years ago, which is exactly why professional advice has become more relevant, not less.

Key Takeaways

• The Annual Exempt Amount is £3,000 for individuals — a steep drop from £12,300 just a few tax years ago.
• UK property sales must be reported and paid within 60 days of completion, separate from your normal Self Assessment deadline.
• CGT rates were unified in October 2024 — property no longer carries a separate, higher rate than shares and other assets.
• Your main home is usually exempt via Private Residence Relief, but second homes and buy-to-lets are fully taxable.
• Business Asset Disposal Relief can reduce the rate on qualifying business sales, subject to a £1 million lifetime limit.
• You must report even if no tax is due, once total disposal proceeds pass £50,000 in the year.

Table of Contents

1. What Does a Capital Gains Tax Accountant Actually Do?
2. When Do You Genuinely Need One?
3. Current CGT Rates and the Annual Exempt Amount
4. The 60-Day Property Reporting Rule
5. Reliefs a CGT Accountant Can Help You Claim
6. What Happens If You Miss a Deadline
7. How Much Does a Capital Gains Tax Accountant Cost?
8. DIY vs a CGT Accountant
9. Capital Gains Tax Advice for London Clients
10. Common Mistakes People Make
11. Accountant Insights: What We See in Practice
12. Do You Need One? (Decision Framework)
13. Checklists
14. FAQs
15. Sources
16. Final Thoughts

What Does a Capital Gains Tax Accountant Actually Do?

A capital gains tax accountant focuses specifically on the tax owed when you dispose of an asset — through a sale, a gift, or occasionally other forms of transfer — that has increased in value since you acquired it. Their work typically covers:

• Calculating the actual gain, factoring in the original purchase price, allowable costs (legal fees, agent fees, improvement costs), and any relevant reliefs.
• Identifying which reliefs apply — Private Residence Relief, Business Asset Disposal Relief, Investors’ Relief, or reliefs for non-UK residents, depending on the asset and circumstances.
• Meeting the correct reporting deadline — the 60-day window for UK property, or the standard Self Assessment deadline for shares, crypto, and other assets.
• Planning disposals in advance, such as timing a sale to make the most of the Annual Exempt Amount or spreading disposals across tax years where appropriate.
• Handling more complex scenarios, including overseas property, carried interest, or disposals involving trusts.

The distinction between calculating the tax correctly and planning the disposal well in advance is where most of the real value tends to sit — a good CGT accountant is often more useful before a sale completes than after.

When Do You Genuinely Need One?

Not every disposal requires professional input, but a few situations consistently benefit from it:

• Selling a second property or buy-to-let, where the 60-day reporting rule applies and the numbers involved are often substantial.
• Disposing of shares or an investment portfolio outside a tax-efficient wrapper like an ISA or pension.
• Selling all or part of a business, where Business Asset Disposal Relief could significantly reduce the rate if the qualifying conditions are met.
• Disposing of cryptocurrency, which is treated as a chargeable asset for CGT purposes and is an area many people underestimate.
• Gifting an asset to someone other than a spouse or civil partner, which is treated as a disposal at market value even though no money changes hands.
• Being a non-UK resident disposing of UK property, where specific rules and reliefs interact with international tax treaties.

Current CGT Rates and the Annual Exempt Amount

Since the rate changes brought in from October 2024, property no longer sits in a separate, higher-rate bracket — most assets, including residential property, now follow the same structure:

Where a gain straddles the basic rate threshold, part of it is taxed at 18% and the remainder at 24% — a calculation that needs to be worked out individually for each disposal.

The Annual Exempt Amount — the portion of gain you can make before any CGT is due — currently stands at £3,000 for individuals, a significant fall from £12,300 as recently as the 2022/23 tax year. Trustees receive a reduced exemption, typically £1,500. Because this allowance has shrunk so sharply, considerably more people now find themselves with a reportable, and often taxable, gain than would have been the case just a few years ago.

The 60-Day Property Reporting Rule

UK residential property is treated differently from other assets when it comes to timing. Rather than waiting until your annual Self Assessment deadline, any CGT owed on a UK property disposal must be reported and paid within 60 days of completion, using HMRC’s dedicated “Capital Gains Tax on UK Property” online service.

This applies whether the property is a buy-to-let, a second home, or an inherited property being sold — anything other than your main residence, which is generally covered by Private Residence Relief instead. Sellers frequently underestimate how quickly 60 days passes once solicitors, valuations, and cost records need to be pulled together, which is exactly why this deadline catches out more people than the standard January one ever does.

Reliefs a CGT Accountant Can Help You Claim

Several reliefs can meaningfully reduce a CGT bill, though each comes with its own qualifying conditions:

• Private Residence Relief — generally exempts the sale of your main home from CGT, though periods of letting or business use can complicate the calculation.
• Business Asset Disposal Relief (BADR) — a reduced rate on qualifying business sales, subject to a £1 million lifetime limit, with the applicable rate having increased in recent Budgets, so current figures should always be confirmed before a sale.
• Investors’ Relief — a reduced rate on gains from newly issued shares in unlisted UK trading companies, provided they’ve been held for at least three years, also subject to a £1 million lifetime limit.
• ISA and pension wrappers — gains inside these accounts are entirely outside CGT, which is why disposals held within a wrapper never generate a reportable gain.
• Reliefs for non-UK residents — specific provisions apply to those who are temporarily non-resident or whose assets derive value from UK land, often requiring specialist cross-border advice.

Accountant Insight: Business Asset Disposal Relief and Investors’ Relief are two of the most valuable reliefs available, but also two of the most commonly misapplied — the qualifying conditions around shareholding percentage, holding period, and company trading status are specific enough that a straightforward mistake can mean losing the relief entirely rather than simply reducing it.

What Happens If You Miss a Deadline

Missing the 60-day property reporting window, or the standard Self Assessment deadline for other assets, triggers HMRC’s usual escalating penalty structure — an initial fixed penalty, followed by further charges the longer the delay continues, plus interest accruing on any unpaid tax. Because CGT liabilities on property sales can run into thousands of pounds, a missed deadline here tends to carry a noticeably higher cost in absolute terms than a similar delay on a smaller Self Assessment matter.

Illustrative Example: Someone selling a buy-to-let property for a £60,000 gain, who’s unaware of the 60-day rule and only reports it through their next Self Assessment return several months later, could face both a late filing penalty on the property disposal itself and interest accruing on the CGT owed for the entire intervening period.

How Much Does a Capital Gains Tax Accountant Cost?

Pricing generally reflects the complexity of the disposal rather than a flat, one-size-fits-all fee:

Given how much a correctly applied relief can save compared to the fee involved, CGT is one of the areas where professional advice most reliably pays for itself — particularly for larger disposals where even a small percentage difference in rate translates into a significant sum.

DIY vs a CGT Accountant

Capital Gains Tax Advice for London Clients

London’s property market means CGT questions come up constantly here — second homes, inherited flats, and buy-to-lets in high-value areas can generate gains substantial enough that even a small difference in relief application has a meaningful financial impact. The capital’s concentration of shareholders, company founders, and investment property owners also means Business Asset Disposal Relief and portfolio disposals come up more frequently than in many other parts of the UK.

Because property values in London tend to run higher than the national average, the numbers involved in a single disposal are often larger — which makes getting the reliefs and timing right correspondingly more valuable. A London-based property sale that misses the 60-day window, or a share disposal that overlooks an available relief, typically carries a bigger absolute cost here than the same mistake might elsewhere in the UK, simply because of the values involved.

Common Mistakes People Make

1. Not realising the 60-day property rule exists
Why it happens: Many people still assume all tax reporting happens through the January Self Assessment deadline.
Consequence: Missing the 60-day window triggers penalties and interest, separate from any Self Assessment obligations.
How to avoid it: Report and pay CGT on a UK property disposal within 60 days of completion, using HMRC’s dedicated online service.

2. Forgetting that gifting an asset still counts as a disposal
Why it happens: No money changes hands, so it doesn’t feel like a taxable event.
Consequence: A gift to anyone other than a spouse or civil partner is treated as a disposal at market value, potentially triggering a CGT bill with no cash received to cover it.
How to avoid it: Get the market value assessed and factor in the CGT position before gifting a significant asset.

3. Overlooking allowable costs that reduce the gain
Why it happens: People often only think to deduct the original purchase price.
Consequence: Overpaying tax by not claiming legal fees, agent fees, stamp duty, or genuine improvement costs.
How to avoid it: Keep records of every cost connected to buying, improving, and selling the asset, not just the purchase price.

4. Applying for Business Asset Disposal Relief without checking eligibility
Why it happens: The relief is well known, so people assume it automatically applies to any business sale.
Consequence: A rejected claim, or worse, an incorrect claim that HMRC later challenges.
How to avoid it: Have a specialist check shareholding percentage, holding period, and trading status against the qualifying conditions before relying on the relief.

5. Assuming the Annual Exempt Amount still works the way it used to
Why it happens: The allowance was £12,300 not long ago, and outdated information still circulates.
Consequence: Underestimating a tax bill by assuming a far larger tax-free amount than the current £3,000 figure.
How to avoid it: Always check the current Annual Exempt Amount before estimating a CGT liability, since it has changed significantly in recent years.

Accountant Insights: What We See in Practice

• The 60-day property rule catches out even experienced sellers — it’s a relatively recent change, and old assumptions about “just doing it through Self Assessment” persist longer than the rule itself.
• Landlords selling for the first time in years are the group most likely to underestimate their bill, largely because the shrinking Annual Exempt Amount has changed the maths considerably since their last disposal.
• Business owners often leave BADR planning too late — the qualifying conditions are far easier to arrange in advance of a sale than to retrofit once a deal is already agreed.
• Crypto disposals are frequently under-reported, not through deliberate avoidance but because people simply don’t realise a token swap or sale counts as a chargeable disposal.
• Spreading disposals across more than one tax year, where practical, is one of the simplest legitimate ways to make better use of the Annual Exempt Amount — and it’s most effective when planned well before a sale, not after.

Do You Need One?

A quick framework to work through:

Step 1: Identify the asset type and value.
Property and business disposals carry tighter deadlines and larger sums, both of which increase the value of professional input.

Step 2: Check whether a relief might apply.
If Private Residence Relief, BADR, or Investors’ Relief could realistically apply, it’s worth having eligibility confirmed properly.

Step 3: Consider the deadline you’re working against.
The 60-day property window leaves little margin for error, which weighs in favour of getting help early rather than scrambling near the deadline.

Step 4: Think about future disposals, not just this one.
If more disposals are likely in future years, planning advice now can shape how and when you sell later.

Checklists

Checklist 1: Before Selling an Asset

• ✓ Confirm whether the 60-day property rule applies to this disposal
• ✓ Gather records of the original purchase price and all allowable costs
• ✓ Check whether Private Residence Relief, BADR, or Investors’ Relief could apply
• ✓ Check the current Annual Exempt Amount before estimating any liability
• ✓ Consider whether timing the disposal across tax years could help

Checklist 2: Property Disposal Specifically

• ✓ Note the exact completion date, since the 60-day clock starts then
• ✓ Register for HMRC’s Capital Gains Tax on UK Property service in advance
• ✓ Confirm whether any part of the property qualifies for Private Residence Relief
• ✓ Have funds available to pay within the 60-day window
• ✓ Keep solicitor and agent invoices as allowable cost evidence

FAQs

What does a capital gains tax accountant do?
They calculate the tax owed on a disposal, identify applicable reliefs, and ensure the gain is reported to HMRC correctly and within the relevant deadline.

How much is the Capital Gains Tax allowance in the UK?
The Annual Exempt Amount is £3,000 for individuals, a significant reduction from £12,300 a few tax years ago.

Do I have to report a property sale within 60 days?
Yes — UK property disposals must be reported and any tax paid within 60 days of completion, separately from the standard Self Assessment deadline.

Is my main home exempt from Capital Gains Tax?
Generally yes, under Private Residence Relief, though periods of letting or business use of the property can affect the exemption.

What is Business Asset Disposal Relief?
A relief offering a reduced CGT rate on qualifying business sales, subject to a lifetime limit, with specific conditions around shareholding and trading status.

Do I need to report crypto gains for CGT?
Yes — disposing of cryptocurrency, including swapping between tokens, is treated as a chargeable event for Capital Gains Tax purposes.

How much does a capital gains tax accountant cost?
Typically £150–£500 for a single property or share disposal, rising to £500 or more for complex business sale calculations.

What happens if I gift an asset instead of selling it?
Gifting to anyone other than a spouse or civil partner is still treated as a disposal at market value, and can trigger a CGT liability.

What counts as an allowable cost against a capital gain?
Costs directly linked to acquiring, improving, or disposing of the asset — such as legal fees, agent fees, and certain improvement costs — can typically be deducted.

What happens if I miss the CGT reporting deadline?
HMRC applies escalating penalties the longer a return remains outstanding, plus interest on any unpaid tax from the original due date.

Sources

• HMRC / GOV.UK — Capital Gains Tax rates and allowances
• GOV.UK — Report and pay Capital Gains Tax on UK property
• GOV.UK — Business Asset Disposal Relief
• GOV.UK — Private Residence Relief

CGT rates, the Annual Exempt Amount, and relief thresholds are set by HMRC and subject to change in future Budgets — always confirm current figures on GOV.UK before publication or before relying on them for a disposal.

Final Thoughts

Capital Gains Tax has become considerably harder to ignore than it once was — a shrinking exempt amount and a tight property reporting window mean far more disposals now carry a genuine tax consequence, and a genuine deadline. Whether you’re selling a second property, a share portfolio, or a business, getting the reliefs and timing right is usually where the real financial difference lies, far more than the calculation itself.

If you’re planning a disposal, or have already completed one and aren’t sure of your reporting obligations, speaking with a qualified accountant early — ideally before the sale completes — gives you the best chance of minimising what’s owed and meeting every deadline involved.

Written by:
Shamayun Chowdhury
Senior Accountant, Major Accountancy
Lecturer in Accounting, Nottingham Trent University
CIMA Qualified, 15+ Years Experience
Last Reviewed: August 2026