Capital Gains Tax Calculator UK 2025

It's a tax on the profit when you sell something that's gone up in value — not the full sale price, just the gain. Sold shares you bought for £10,000 at £25,000? The gain is £15,000, and that's what gets taxed.

Just £3,000 per person. It's been slashed over the past few years — it was £12,300 as recently as 2022/23, then £6,000, and now £3,000. That means almost any meaningful disposal will trigger a CGT bill. If you're married or in a civil partnership, you each get your own £3,000 allowance, so transferring assets between you before selling can double the relief.

For most assets (shares, crypto, etc.): 10% at the basic rate, 20% at higher/additional rate. Residential property is more expensive: 18% and 24%. Business Asset Disposal Relief gets you a flat 10% up to a £1 million lifetime limit. Which rate you pay depends on where the gain sits in your income tax bands — so your salary pushes the gain into higher rate territory.

Here's how it works. Take the sale price, subtract what you paid, subtract improvement costs (extensions, loft conversions — not new carpets), subtract selling costs (estate agent, solicitor), and you've got the gain. Then knock off your £3,000 annual exemption and any losses you're carrying forward. What's left is taxed at 18% or 24%. One thing people forget: you have to report and pay within 60 days of completion, not at the end of the tax year.

It used to be called Entrepreneurs' Relief. If you're selling all or part of a qualifying business, or shares in your personal trading company, you can pay just 10% CGT instead of the normal rates. There's a £1 million lifetime cap on gains that qualify. You need to have held the business or shares for at least two years.

Yes. HMRC treats crypto like any other asset. Selling, swapping one token for another, or spending crypto all count as disposals. The rates are the same as shares: 10% or 20%. Mining and staking rewards are treated as income instead. And HMRC has data-sharing agreements with UK exchanges, so don't assume they won't notice.

Yes, and you should. Losses from the same tax year are deducted automatically. Unused losses carry forward indefinitely — but you have to report them to HMRC within 4 years of the tax year they happened, otherwise you lose them. If you're sitting on underperforming investments, selling at a loss before 5 April to "bank" the loss can be a legitimate tax planning strategy.

It depends on the asset. For residential property, you've got 60 days from completion to report and pay using HMRC's UK Property CGT service. For everything else — shares, crypto, business assets — it goes on your self-assessment return and is due by 31 January following the end of the tax year.

No — your main home is exempt under Private Residence Relief. But there are exceptions that trip people up. If you rented out part of it, used a room exclusively for business, or the garden is over half a hectare, part of the gain could be taxable. The last 9 months of ownership always qualify for relief even if you've already moved out.

Anything that permanently enhanced the property can be deducted from the gain. Extensions, structural renovations, a new bathroom — all count. Repainting, fixing a leaky tap, replacing like-for-like — those don't. Keep your receipts and invoices. HMRC can ask for proof, and "I definitely spent £20,000 on the kitchen" won't cut it without paperwork.