If you're an investor, entrepreneur, or expat with financial interests on both sides of the Atlantic, understanding the United States vs Ireland capital gains tax landscape for the 2025/2026 tax year is essential. Whether you're selling stocks, real estate, or business assets, the tax treatment of your gains can differ dramatically between Washington and Dublin — and those differences can mean thousands of dollars (or euros) in your pocket or owed to the taxman.
In this detailed capital gains tax comparison, we'll walk through the specific rates, exemptions, thresholds, and filing obligations in both the United States and Ireland, highlight the US–Ireland tax treaty provisions, and offer practical examples to help you plan more effectively.
How Capital Gains Tax Works: A Quick Overview
Capital gains tax (CGT) is levied on the profit you make when you sell or dispose of an asset that has increased in value. Both the United States and Ireland impose CGT, but the structures are fundamentally different.
- In the United States, capital gains are split into short-term and long-term categories, with preferential rates for assets held longer than one year.
- In Ireland, there is a single flat rate applied to most capital gains, regardless of how long you held the asset.
This structural difference is the most important distinction in any tax comparison United States Ireland analysis and sets the stage for everything that follows.
United States Capital Gains Tax Rates in 2025/2026
The US tax system distinguishes between short-term and long-term capital gains, and your tax rate depends on your total taxable income and filing status.
Short-Term Capital Gains
Short-term capital gains apply to assets held for one year or less. These gains are taxed as ordinary income, meaning they are added to your other income and taxed at your marginal federal income tax rate. For 2025, federal ordinary income tax brackets range from 10% to 37%.
Long-Term Capital Gains
Long-term capital gains apply to assets held for more than one year and benefit from significantly lower tax rates. For the 2025 tax year, the federal long-term capital gains rates are:
| Filing Status | 0% Rate Up To | 15% Rate Up To | 20% Rate Above |
|---|---|---|---|
| Single | $48,350 | $533,400 | $533,400+ |
| Married Filing Jointly | $96,700 | $600,050 | $600,050+ |
| Head of Household | $64,750 | $566,700 | $566,700+ |
Net Investment Income Tax (NIIT)
High-income taxpayers in the US may also owe an additional 3.8% Net Investment Income Tax (NIIT) on capital gains if their modified adjusted gross income exceeds:
- $200,000 for single filers
- $250,000 for married filing jointly
This can push the effective top federal rate on long-term capital gains to 23.8%.
State-Level Capital Gains Taxes
Unlike Ireland, the US has state-level taxes that can significantly increase your total CGT burden. States like California impose rates up to 13.3% on capital gains, while states like Florida, Texas, and Nevada have no state income tax at all. When comparing US capital gains tax to Ireland's, it's critical to factor in your state of residence.
Use our United States Capital Gains Tax Calculator to estimate your exact federal and state liability based on your specific situation.
Ireland Capital Gains Tax Rates in 2025/2026
Ireland's capital gains tax system is simpler in structure but carries a notably higher headline rate.
The Standard CGT Rate
Ireland applies a flat rate of 33% on most capital gains for the 2025/2026 tax year. This rate applies regardless of:
- How long you held the asset
- Your total income level
- Your filing status
This is one of the highest CGT rates in the OECD and stands in stark contrast to the US system's preferential long-term rates.
Annual CGT Exemption
Ireland provides a modest annual personal exemption of €1,270 per individual. The first €1,270 of capital gains in any tax year is tax-free. This exemption is per person, so a married couple can collectively shelter up to €2,540 in gains annually.
Entrepreneur Relief
Ireland offers a reduced CGT rate of 10% on qualifying business disposals under the Revised Entrepreneur Relief scheme. This applies to:
- Gains on the disposal of qualifying business assets
- A lifetime limit of €1 million in chargeable gains
- The individual must have owned and been actively involved in the business for at least 3 continuous years in the 5 years prior to disposal
This relief is somewhat analogous to the favorable US treatment of Qualified Small Business Stock (QSBS) under Section 1202, though the specifics differ significantly.
Filing and Payment Deadlines
Ireland has a unique two-period payment system for CGT:
- Initial period (January 1 – November 30): Tax on gains realized in this period must be paid by December 15 of the same year.
- Later period (December 1 – December 31): Tax on gains realized in December must be paid by January 31 of the following year.
- The annual CGT return is due by October 31 of the following year (or mid-November if filing online via ROS).
Use our Ireland Capital Gains Tax Calculator to quickly estimate your Irish CGT liability.
Side-by-Side Comparison: United States vs Ireland Capital Gains Tax
Here's a clear summary table to illustrate the key differences in the capital gains tax comparison between the two countries:
| Feature | United States (2025) | Ireland (2025/2026) |
|---|---|---|
| Short-term CGT rate | 10%–37% (ordinary income rates) | 33% (flat rate) |
| Long-term CGT rate | 0%, 15%, or 20% | 33% (flat rate) |
| Holding period for preferential rate | More than 1 year | N/A — no preferential rate |
| Additional surtax | 3.8% NIIT for high earners | None |
| Top effective federal/national rate | 23.8% (federal) | 33% |
| State/local taxes | 0%–13.3% depending on state | None |
| Annual exemption | None (but 0% bracket exists) | €1,270 per person |
| Entrepreneur/business relief | QSBS exclusion (up to 100%) | 10% rate on up to €1M lifetime gains |
| Primary residence exemption | Up to $250K/$500K gain excluded | Principal private residence relief (full exemption) |
| Tax year | Calendar year (Jan–Dec) | Calendar year (Jan–Dec) |
Practical Example: Selling Shares Worth $100,000 in Profit
Let's compare the tax owed on a $100,000 (approximately €92,000) capital gain from selling publicly traded shares held for more than one year:
In the United States (single filer, $150,000 total income, no state tax):
- Long-term capital gains rate: 15%
- Federal CGT owed: $15,000
- NIIT: Not applicable (income below $200,000 threshold)
- Total tax: $15,000 (15%)
In Ireland:
- Taxable gain: €92,000 – €1,270 exemption = €90,730
- CGT rate: 33%
- Total tax: €29,941 (approximately 32.5% effective rate)
In this scenario, the Irish taxpayer pays roughly double the capital gains tax compared to the American taxpayer. The difference becomes even more dramatic in US states with no income tax.
You can run your own scenarios using our United States Capital Gains Tax Calculator and Ireland Capital Gains Tax Calculator.
The US–Ireland Double Taxation Treaty and Capital Gains
The United States and Ireland have a bilateral tax treaty (the Convention for the Avoidance of Double Taxation) that addresses how capital gains are taxed when individuals or entities have tax obligations in both jurisdictions.
Key Treaty Provisions for Capital Gains
- Real property (immovable property): Gains from the sale of real estate are generally taxable in the country where the property is located. If a US resident sells Irish property, Ireland has the primary right to tax the gain.
- Business assets of a permanent establishment: Gains attributable to a permanent establishment are taxable in the country where the PE is situated.
- Shares and securities: Generally, gains from selling shares are taxable only in the country of residence of the seller. A US resident selling Irish company shares would typically be taxed only in the US (and vice versa).
- Foreign tax credits: Where double taxation does occur, the treaty ensures relief through foreign tax credits. A US citizen living in Ireland who pays Irish CGT at 33% can generally claim a credit against their US tax liability on the same gain, and vice versa.
US Citizens and Green Card Holders in Ireland
The United States taxes its citizens and permanent residents on worldwide income, regardless of where they live. This means a US citizen residing in Ireland must:
- Report capital gains to both the IRS and Irish Revenue
- Pay Irish CGT of 33% on gains arising in Ireland
- Claim a foreign tax credit on their US return to offset the Irish tax paid
- Since Ireland's 33% rate typically exceeds the US rate, little or no additional US tax is usually owed — but reporting is still mandatory
Failure to file with the IRS can result in significant penalties, even if no additional tax is due. Use our United States Income Tax Calculator alongside the capital gains calculator to understand your full US filing obligations.
Special Considerations and Common Mistakes
Primary Residence Exemptions
Both countries offer valuable exemptions for your main home, but they work differently:
- United States: Under Section 121, you can exclude up to $250,000 ($500,000 for married couples filing jointly) of gain on the sale of your primary residence if you've lived in and owned it for at least 2 of the last 5 years.
- Ireland: The Principal Private Residence (PPR) relief provides a full exemption from CGT on gains from selling your main home, with no monetary cap. However, the relief is proportionally reduced for periods when the property was not your primary residence or was used for business purposes.
Currency Conversion Issues
For individuals with assets in both jurisdictions, currency fluctuations can create phantom gains or losses. For example, a US citizen in Ireland buying an asset in euros may have a gain in dollar terms even if the euro value hasn't changed, simply due to exchange rate movements. The IRS requires gains to be calculated and reported in US dollars.
Cryptocurrency and Digital Assets
Both the US and Ireland treat cryptocurrency disposals as taxable capital gains events:
- In the US, the IRS treats crypto as property, subject to the standard short-term/long-term framework.
- In Ireland, Revenue treats crypto gains as subject to the standard 33% CGT rate with the €1,270 annual exemption.
Common Mistakes to Avoid
- Forgetting state taxes in the US: Many taxpayers focus only on federal rates and are surprised by an additional state bill.
- Missing Ireland's split payment deadlines: Unlike the US, which has a single April filing date, Ireland requires mid-year CGT payments in December.
- Not claiming foreign tax credits: Dual filers often overpay by failing to claim treaty-based credits.
- Ignoring cost basis adjustments: Both countries have specific rules for calculating your cost basis (or base cost in Irish terminology), including adjustments for improvements, inflation indexation (Ireland eliminated indexation for disposals after 2003), and acquisition costs.
- Assuming tax residency is straightforward: Both the US and Ireland have nuanced rules for determining tax residency. Ireland uses the 183-day rule (or 280 days over two years), while the US considers citizenship, green card status, and the substantial presence test.
Frequently Asked Questions
Is capital gains tax higher in the US or Ireland?
For most investors, Ireland's flat 33% rate results in a higher tax bill than the US federal long-term capital gains rate of 0–20% (plus potential 3.8% NIIT). However, when US state taxes are added (up to 13.3%), the gap narrows significantly in high-tax states. For short-term gains, the US can be equally expensive for high-income earners (up to 37% + 3.8% + state taxes).
Do I have to pay capital gains tax in both countries?
If you are a tax resident of both countries, you may have reporting obligations in both. However, the US–Ireland tax treaty provides mechanisms to avoid true double taxation, primarily through foreign tax credits. You should not end up paying the full rate in both countries on the same gain.
Can I use losses to offset gains in both countries?
Yes. Both the US and Ireland allow you to offset capital losses against capital gains. In the US, you can also deduct up to $3,000 of net capital losses against ordinary income per year, with excess losses carried forward. In Ireland, unused losses can be carried forward indefinitely against future gains but cannot be offset against income.
What about inheritance and gifted assets?
The US uses a stepped-up basis at death, meaning heirs receive assets at their current market value, potentially eliminating capital gains tax on decades of appreciation. Ireland handles inherited assets through Capital Acquisitions Tax (CAT) rather than CGT, with different thresholds and rates. Gifted assets in Ireland are generally deemed disposed at market value for CGT purposes.
Explore more tax scenarios with our Ireland Income Tax Calculator and United States Income Tax Calculator.
Conclusion: Key Takeaways for 2025/2026
The United States vs Ireland capital gains tax comparison reveals two fundamentally different approaches:
- The US rewards long-term holding with preferential rates as low as 0%, but the system is complex with federal, state, and surtax layers.
- Ireland keeps it simple with a flat 33% rate, but this simplicity comes at a cost — there's no benefit to holding assets longer, and the rate is nearly double the standard US long-term rate.
- The US–Ireland tax treaty is your best friend if you have obligations in both countries. Proper use of foreign tax credits can prevent double taxation.
- Entrepreneur and primary residence reliefs exist in both systems but work very differently — understanding the specifics can save you tens of thousands.
For anyone managing cross-border investments or considering a move between the US and Ireland, professional tax advice is essential. In the meantime, model your potential liabilities using our United States Capital Gains Tax Calculator and Ireland Capital Gains Tax Calculator to get a clearer picture of where you stand.
This article is for informational purposes only and does not constitute tax advice. Tax laws change frequently; consult a qualified tax professional for advice specific to your situation.