Capital Gains Tax Calculator

Estimate US capital gains tax on investments. Calculates short-term vs long-term rates, net investment income tax, and after-tax profit.

A capital gains tax (CGT) calculator estimates the tax owed when you sell or dispose of an asset that has increased in value. CGT typically applies to gains on investments (shares, funds), second or investment properties, business assets, and personal possessions above a minimum threshold. The gain is the difference between the sale proceeds and the allowable cost (original purchase price plus eligible improvement and transaction costs). CGT does not typically apply to gains on your primary residence in most jurisdictions, and assets held in tax-advantaged wrappers (ISAs, 401(k), etc.) are usually exempt. Loan Payment Calculator and Mortgage Calculator provide important related context.

CGT rates and rules vary significantly by country: some jurisdictions tax capital gains as ordinary income; others apply preferential rates for long-term holdings; and many offer annual exempt allowances that allow a certain amount of gains tax-free. Understanding the rules in your specific jurisdiction — including available reliefs and reporting deadlines — is essential before disposing of any significant asset.

Enter the sale proceeds (the amount you received for the asset).
Enter the original purchase cost (including transaction costs on purchase).
Enter any allowable improvement costs (for property: structural improvements, not routine maintenance).
Enter transaction costs on sale (agent fees, legal fees).
Enter any annual exempt allowance applicable in your jurisdiction (e.g. 3,000 in the UK for 2024/25; 3,000 for long-term gains in the US before income tax on amounts above).
Select your income tax bracket to apply the correct CGT rate — rates vary significantly by country and holding period.

Capital gains tax calculation

Net gain = Sale proceeds − Purchase cost − Allowable costs − Selling costs

Taxable gain = Net gain − Annual exempt allowance

CGT owed = Taxable gain × Applicable CGT rate

CGT rates vary by jurisdiction: UK (2024) — 18–24% on most assets; US — 0%, 15%, or 20% for long-term gains (held 1+ years) depending on income; Australia — 50% discount on gains for assets held 1+ years, then taxed at marginal rate; Canada — 50% of gain included in income and taxed at marginal rate.

Worked example: Asset purchased for 50,000 (plus 2,000 in costs), sold for 120,000 (less 3,000 selling costs). Net gain = 120,000 − 50,000 − 2,000 − 3,000 = 65,000. Less annual exempt allowance 3,000 = 62,000 taxable. At 20% CGT rate: 12,400 owed.

Understanding your CGT result

Key CGT reliefs globally

Major CGT reliefs across jurisdictions: primary residence exemption (most countries exempt gains on your main home); long-term holding discounts (US: 0%/15%/20% vs short-term ordinary income rates; Australia: 50% discount after 12 months); business disposal reliefs (UK Business Asset Disposal Relief at 10%; US Section 1202 exclusion for qualified small business stock); tax-advantaged account exemptions (ISA, Roth IRA, pension wrappers shelter gains from CGT completely); annual exempt amounts (UK: 3,000; varies by country). Consult a local tax adviser to ensure you claim all available reliefs.

Finance tips and best practices

Use your annual exempt allowance every year — in jurisdictions where this cannot be carried forward, consider crystallising gains up to the exempt amount each year even if not selling.
Transfer assets to a spouse or partner before sale where permitted — each person typically has their own exempt allowance and rate band, potentially halving the effective CGT rate on a shared gain.
Keep records of all acquisition costs, improvement costs, and transaction costs from the time of purchase — these reduce the taxable gain and are often lost years after a transaction.
Understand reporting deadlines — some jurisdictions (UK for residential property) require CGT to be reported and paid within 60 days of disposal; missing these deadlines triggers automatic penalties.
Use tax-advantaged investment wrappers to shelter future gains — moving assets from a taxable account into a pension or ISA equivalent eliminates CGT on future growth.

In the UK, HMRC collected approximately 14.4 billion in CGT in 2022/23 — up from 6.5 billion in 2020/21, largely driven by rising property and equity values (HMRC, 2024).
In the US, long-term capital gains rates are 0% for lower-income earners, 15% for most middle-income taxpayers, and 20% for higher earners — significantly lower than ordinary income rates (IRS, 2024).
Australia's 50% CGT discount for assets held over 12 months effectively halves the tax on long-term investment gains, making asset holding period a significant planning consideration.
The primary residence exemption is one of the most valuable tax reliefs available to most people — in most countries, gains on your main home are completely exempt from CGT.

Common mistakes to avoid

Not reporting disposals within required deadlines — late reporting triggers automatic penalties in most jurisdictions regardless of whether tax is owed.
Forgetting allowable costs — purchase transaction costs, legal fees, and genuine improvement costs all reduce the gain; these must be documented from purchase date.
Confusing income tax rates with CGT rates — CGT and income tax are typically calculated separately; your income determines which CGT rate band applies but does not merge with income tax.
Not seeking advice on asset-specific reliefs before selling — various reliefs (business disposal, rollover, gift hold-over) can dramatically reduce or defer CGT liability if applied correctly.

Capital gains tax rules vary significantly by jurisdiction, asset type, and holding period. This calculator provides a generic illustration only — actual CGT liability depends on the specific rules, rates, reliefs, and reporting requirements in your country and tax year. CGT laws change regularly and this tool does not constitute tax advice. Always consult a qualified tax adviser or accountant authorised in your jurisdiction before disposing of significant assets. In the UK, HMRC's Capital Gains Tax helpline and manuals provide authoritative guidance; in the US, IRS Publication 550 covers investment income and expenses.