How to Use the UK Capital Gains Tax Calculator
The UK Capital Gains Tax Calculator computes your CGT liability for 2025/26 on property disposals, share sales, cryptocurrency, business assets, and other chargeable assets. It applies the correct rates based on your income tax band and asset type, including the new October 2024 rate changes.
Enter your capital gain, any allowable costs (legal fees, improvement costs), and your total income for the year. The calculator deducts the annual CGT exempt amount (£3,000 for 2025/26), allocates any remaining basic rate band you have, and applies 18% or 24% for residential property, or 10% or 20% for other assets.
A key nuance is the interaction with your income tax band. Your capital gain sits on top of your income for the purpose of calculating which CGT rate applies. If you earn £35,000 and have a £20,000 gain, the first £15,270 of the gain (up to the £50,270 higher rate threshold) is taxed at the lower rate, and only £4,730 at the higher rate.
📊 Worked Example
Selling a buy-to-let property for £320,000 (bought for £220,000), income £40,000:
- Gross gain: £100,000
- Less annual exempt amount: −£3,000
- Taxable gain: £97,000
- 18% on £10,270 (basic rate band): £1,849
- 24% on £86,730 (higher rate): £20,815 — Total CGT: £22,664
Common Use Cases
- ✅ Calculating CGT before selling a buy-to-let or second property
- ✅ Working out tax on share or fund gains (including crypto)
- ✅ Planning whether to spread a gain across two tax years
- ✅ Checking if you have any unused losses to offset against gains
- ✅ Understanding whether Business Asset Disposal Relief reduces your rate
- ✅ Calculating CGT when gifting assets to a spouse or civil partner
Frequently Asked Questions
What are the UK CGT rates for 2025/26?
For residential property: 18% (basic rate taxpayers) and 24% (higher/additional rate taxpayers). For other assets (shares, crypto, business assets): 10% (basic rate) and 20% (higher rate). Business Asset Disposal Relief (BADR) applies 10% to qualifying business disposals up to a £1 million lifetime limit. These rates changed from October 2024.
What is the annual CGT exempt amount?
The annual exempt amount (AEA) is £3,000 for 2025/26. This means the first £3,000 of net gains each year is tax-free. The AEA has been reduced significantly from £12,300 in 2022/23 to encourage CGT receipts. It applies to individuals (not trusts, which have a £1,500 AEA).
Can married couples use each other's annual exempt amount?
Married couples and civil partners can transfer assets between themselves at cost (no CGT between spouses). This means a couple can each use their own £3,000 AEA, potentially sheltering £6,000 of gains. They can also use each other's basic rate band to reduce the applicable CGT rate.
When must I pay and report CGT?
From April 2020, residential property gains must be reported and paid within 60 days of completion using HMRC's CGT on UK Property service. Other gains are reported via the annual self-assessment tax return, with payment due by 31 January following the tax year. Late payment incurs interest and penalties.
What costs can I deduct from a capital gain?
Allowable costs include: original purchase price, purchase costs (stamp duty, legal fees, surveys), improvement costs (not repairs/maintenance), costs of sale (estate agent fees, legal fees), and any enhancement expenditure that adds value. You cannot deduct mortgage interest or ongoing maintenance costs.