Capital Gains Tax Calculator 2026

Capital Gains Tax in 2026

Capital gains tax (CGT) is paid on the profit you make when selling an asset such as shares, property, or cryptocurrency. The rate depends on how long you held the asset, your income, and which country you're in. Holding an asset for more than one year typically results in a significantly lower tax rate.

2026 CGT Rates at a Glance

Gains Stack on Top of Your Income

This is the mechanic that surprises people most, and it is why the same gain produces a different bill for two different people. A capital gain is not taxed in isolation — it sits on top of your other income, and the rate depends on where it lands once stacked.

In the UK, subtract the £3,000 annual exempt amount first, then the remainder is charged at 18% for whatever still fits inside your basic-rate band and 24% above it. Someone earning £30,000 with a £20,000 gain pays 18% on most of it; someone earning £70,000 with the identical gain pays 24% on all of it, because their income has already used up the basic-rate band.

In the US, long-term gains have their own 0%/15%/20% schedule, but the band you land in is decided by your total taxable income including the gain. A single filer with $60,000 of income has already passed the $49,450 ceiling of the 0% band, so a $20,000 long-term gain is taxed at 15% — about $3,000. Had their income been low enough in that year, some or all of it could have been taxed at nothing.

Timing Is the Largest Lever You Control

You rarely choose the size of a gain, but you usually choose when to realise it — and that decision moves the tax more than anything else:

• Hold past one year (US). Selling at 364 days makes the gain short-term, taxed as ordinary income at up to 37%. Selling at 366 days caps it at 20% and often 15%. Nothing else about the transaction changes.
• Use each year's allowance (UK). The £3,000 exemption cannot be carried forward — unused, it is simply lost. Splitting a large disposal across two tax years captures it twice.
• Realise in a low-income year. A career break, a sabbatical or a year of self-employment losses can drop you into a lower CGT band, sometimes the US 0% band entirely.
• Harvest losses. Losses on other assets offset gains in the same year. In the UK unused losses can be carried forward indefinitely once reported to HMRC.

Married couples have an additional option: transfers between spouses are exempt in both countries, so moving an asset before sale can use two annual allowances and potentially two lower rate bands instead of one.

What Counts as a Disposal

A common and expensive assumption is that tax is only due when money reaches your bank account. Both HMRC and the IRS treat a disposal far more broadly: selling, gifting to anyone other than a spouse, swapping one asset for another, or spending an asset all count. Crypto is the clearest case — trading one token for another, or paying for something with it, is a taxable event even though no currency was withdrawn.

Two further points catch people out. A main residence is generally exempt in the UK under Private Residence Relief and benefits from a large exclusion in the US, but second homes and buy-to-let property are fully within scope — and UK residential property gains must be reported and paid within 60 days of completion, not at the next self-assessment deadline. High earners in the US should also expect the 3.8% Net Investment Income Tax on top once income exceeds $200,000 single or $250,000 married.

Frequently Asked Questions