What is a capital gain?

It is the profit on the disposal of a capital asset (sale, gift, exchange), usually calculated as proceeds minus cost basis and allowable costs.

Do I pay tax on the full sale price?

No. Capital gains tax generally applies to the gain only (after subtracting basis, selling costs, exemptions, and losses).

How do holding periods affect tax?

Many jurisdictions tax short-term gains like ordinary income and offer concessional rates or discounts for long-term holdings. This tool lets you set holding period and jurisdiction to apply rules.

Yes, most systems allow realized capital losses to offset gains (sometimes with carryovers). Enter losses in the calculator to reduce your taxable gain.

What about main residence or primary home exclusions?

Rules vary. Use the Exclusions input to model country-specific reliefs such as US Section 121, UK Private Residence Relief, AU Main Residence exemption, etc.

Are the presets legal advice?

No. Presets are for educational modeling and are editable. Always verify current rates and rules with official sources or a qualified tax professional.

Capital Gains Tax Calculator

Authoritative Data Source & Methodology

This tool models widely used CGT frameworks: cost-basis approach, allowances, loss offset, and jurisdiction-specific treatments for holding period discounts or inclusion. Official references include:

United States — IRS Publication 550 & Schedule D instructions: Publication 550, Schedule D Instructions
United Kingdom — GOV.UK CGT rates & allowances: Rates, Guidance
Australia — ATO: Calculating your CGT, Guide to CGT 2025
Ireland — Revenue: How to calculate CGT
South Africa — SARS: Capital Gains Tax overview and rates

“Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.”

The Formula Explained

\[ \textbf{Gain} = P_{\text{sale}} - \big( B_{\text{cost}} + C_{\text{sell}} \big) \] \[ \textbf{Net Gain Before Reliefs} = \max(0,\ \text{Gain} - E_{\text{exclusions}} ) \] \[ \textbf{Taxable Gain} = \max\big(0,\ \text{Net Gain Before Reliefs} - A_{\text{allowance}} - L_{\text{losses}}\big) \] \[ \textbf{Jurisdiction Adjustments} = \begin{cases} \text{US: } \text{ST} \to t_{\text{ST}},\ \text{LT} \to t_{\text{LT}} \\ \text{UK: } t_{\text{asset,band}} \\ \text{AU: } \text{if LT} \Rightarrow 50\% \text{ discount} \\ \text{IE: } 33\% \ (\text{typical}) \\ \text{ZA: } \text{include } 40\% \text{ of gain then apply marginal rate} \end{cases} \] \[ \textbf{Tax} = \text{Taxable Gain}_{\text{(after adjustments)}} \times t \quad ; \quad \textbf{After-Tax Proceeds} = P_{\text{sale}} - \text{Tax} \]

Glossary of Variables

Sale proceeds ($P_{\text{sale}}$): total consideration received.
Cost basis ($B_{\text{cost}}$): purchase price plus capital improvements.
Selling costs ($C_{\text{sell}}$): commissions, legal fees, transfer taxes.
Exclusions ($E_{\text{exclusions}}$): jurisdiction-specific relief amounts (e.g., main residence).
Annual allowance ($A_{\text{allowance}}$): yearly tax-free gain amount where applicable.
Losses ($L_{\text{losses}}$): realized losses available to offset gains.
LT/ST rates ($t_{\text{LT}}, t_{\text{ST}}$): effective tax rates for long/short-term gains.

How It Works: A Step-by-Step Example

Scenario: You sell shares for $25,000. Basis + improvements $12,000; selling costs $200; no exclusions; losses $1,000; allowance $0. Long-term; US preset with $t_{\text{LT}}=15\%$.

Gain: $25{,}000 - (12{,}000 + 200) = 12{,}800$.
Net before reliefs: $12{,}800 - 0 = 12{,}800$.
Taxable: $12{,}800 - 0 - 1{,}000 = 11{,}800$.
Tax: $11{,}800 \times 0.15 = 1{,}770$.
After-tax proceeds: $25{,}000 - 1{,}770 = 23{,}230$.

Frequently Asked Questions

Does the tool handle different countries?

Yes — pick a preset to load typical rules (editable), or choose Custom and set your own rates/allowances.

How precise are the presets?

They are educational defaults. Exact tax depends on full circumstances (income bands, relief tests, timing). Always verify with official guidance.

Can I model main residence relief?

Enter the excluded amount in “Exclusions”. See links above for the detailed conditions per jurisdiction.

What about UK bands?

Select UK preset, set asset type, then set rates 18%/24% accordingly based on your band. This tool keeps them editable for transparency.

Australia discount vs rate?

If held ≥12 months, many individuals can discount the gain by 50%, then apply their marginal rate. Toggle “Australia discount”.

South Africa inclusion?

Individuals include a portion (commonly 40%) of the gain in taxable income and then apply their marginal rate. Toggle “South Africa inclusion”.

Tool developed by Ugo Candido. Content reviewed by the CalcDomain Editorial Board.
Last accuracy review: October 30, 2025

Capital Gains Tax Calculator

Calculator

Results

Realized Gain

Taxable Gain

Estimated Tax Due

After-Tax Proceeds