UK Capital Gains Tax (CGT) Calculator
Estimate your UK Capital Gains Tax on residential property and other assets. Built for individuals and trustees, this calculator handles multiple disposals, losses, the Annual Exempt Amount, and the basic-rate band interaction to give a clear, defensible estimate.
Enter your details
Disposals
Add each asset you sold in the tax year. Provide proceeds and allowable costs (purchase price, fees, improvements, selling costs).
Results
Notes: For Individuals, the basic-rate band is assumed at £37,700. For Trusts we apply higher CGT rates to all gains and a simplified trust AEA (half of the individual’s). Calculations are estimations; complex reliefs and special rules may apply.
Data Source and Methodology
Authoritative source: HMRC / GOV.UK — “Work out your gain” and CGT rate guidance. Specific references:
Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.
The Formula Explained
Let each disposal i have proceeds P_i, allowable costs C_i, and gain g_i = P_i - C_i.
We split gains by category: residential property (prop) vs other assets (other).
1) Aggregate gains and losses:
G_prop = Σ max(g_i, 0) for property
G_other = Σ max(g_i, 0) for other
L_disposals = Σ max(-g_i, 0) over all disposals
L_input = losses entered by user (≥ 0)
L_total = L_disposals + L_input
Gross gains (before AEA): G_gross = G_prop + G_other
Net gains before AEA: G_net = max(0, G_gross - L_total)
2) Annual Exempt Amount (AEA):
AEA_y = { 12,300 (2022/23), 6,000 (2023/24), 3,000 (2024/25) } for individuals
For trusts (simplified): AEA_trust = AEA_y / 2
Apply AEA after losses: T = max(0, G_net - AEA)
To preserve rate accuracy, we carry category breakdown through:
Losses applied with priority to property (higher potential rate), then other.
AEA applied to remaining gains with the same priority.
3) Rate interaction with income (Individuals only):
Basic rate band B = 37,700
Unused basic band U = max(0, B - taxable_income)
Split taxable gains between basic and higher bands to minimize tax:
Allocate U first to the category with larger rate differential (Δ = higher_rate - basic_rate).
Tax due:
CGT = G_basic_prop * r_prop_basic + G_high_prop * r_prop_high
+ G_basic_other * r_other_basic + G_high_other * r_other_high
Rates:
2022/23 and 2023/24:
r_other_basic = 10%, r_other_high = 20%
r_prop_basic = 18%, r_prop_high = 28%
2024/25:
r_other_basic = 10%, r_other_high = 20%
r_prop_basic = 18%, r_prop_high = 24%
Trusts (simplified): All gains taxed at higher rates; no basic band.
Glossary of Variables
- P_i: Sale proceeds for disposal i
- C_i: Allowable costs (purchase price, buying/selling fees, qualifying improvements)
- g_i: Individual gain or loss (P_i − C_i)
- G_prop / G_other: Sum of positive gains by category
- L_total: Total losses (from disposals + user-entered losses)
- AEA: Annual Exempt Amount for the selected tax year and filer type
- U: Unused basic-rate band (Individuals) = max(0, 37,700 − taxable income)
- CGT: Capital Gains Tax due after applying rates
Come Funziona: Un Esempio Passo-Passo
Scenario: Individual in 2024/25 with taxable income £32,000. Two disposals:
- Residential property: Proceeds £120,000; Allowable costs £105,000 → gain £15,000
- Shares (other asset): Proceeds £10,000; Allowable costs £7,500 → gain £2,500
Other losses to use: £1,000.
- Gross gains: £15,000 + £2,500 = £17,500
- Losses: £1,000 → Net before AEA: £16,500
- AEA (2024/25): £3,000 → Taxable gains T = £13,500
- Unused basic band U = 37,700 − 32,000 = £5,700
- Rates 2024/25: property 18% basic / 24% higher; other 10% / 20%
- Allocate basic band first to “other” (bigger differential: 10% vs 6%): other taxable up to £2,500 falls in basic band, leaving U = £3,200; remaining basic band applied to property up to £3,200.
- Compute tax: other basic £2,500 × 10% = £250; property basic £3,200 × 18% = £576; remaining property £7,800 at 24% = £1,872.
Estimated CGT: £250 + £576 + £1,872 = £2,698.
Frequently Asked Questions (FAQ)
Which rates and allowances does this calculator use?
It uses HMRC CGT rates and the Annual Exempt Amount for 2022/23, 2023/24, and 2024/25. For 2024/25 the higher rate on residential property is 24% (down from 28%).
How do I estimate my taxable income for CGT?
Use your income after personal allowance for the selected tax year. The calculator uses this to determine any unused basic-rate band.
Do I need to report UK property gains within 60 days?
Yes, UK residential property disposals with CGT due must usually be reported and paid within 60 days of completion via HMRC’s service.
What if my property was my main residence?
Private Residence Relief may exempt some or all of the gain. Tick “Main residence relief” to treat that disposal as exempt in this estimator.
Does the tool handle Business Asset Disposal Relief?
No. This estimator does not model special reliefs like BADR (10% rate). Seek professional advice if reliefs may apply.
Are trust rules fully modeled?
We apply a simplified approach: trust AEA is half the individual AEA and all gains taxed at higher rates. Real-world trust allocations can be more complex.