FAQ 021 | What Is UK Capital Gains Tax (CGT), and When Does It Apply?

Author: SJW Research & Intelligence

Brand: SJW UK Properties

What is UK Capital Gains Tax (CGT)?

When buying a UK property for the first time, most clients focus on the Stamp Duty payable on purchase. For investors holding property over the long term, however, there is another tax that comes up regularly: Capital Gains Tax, usually shortened to CGT.

Clients often ask: “Once I sell the property, will I definitely have to pay Capital Gains Tax?” The answer is: not necessarily. Whether CGT is payable depends on the UK tax rules in force at the time, the use of the property, the ownership structure and the individual’s own circumstances.

What is a capital gain?

In simple terms, a capital gain is the increase in value realised when an asset is sold. If a property sells for more than it was bought for, that increase may, subject to the relevant tax rules, give rise to Capital Gains Tax. CGT is not, however, calculated simply as the sale price less the purchase price. The calculation may also take account of qualifying purchase costs, costs of sale, qualifying improvement expenditure and other tax factors, so every owner’s position may be different.

When might Capital Gains Tax arise?

Under the current UK tax system, the following situations are among those where CGT should be looked at more closely:

 the sale of a buy-to-let investment property;

 the sale of a second home;

 the sale of an investment property held over the long term;

 other situations involving a gain in capital value.

Whether tax is ultimately payable, and how it is calculated, should be assessed against the tax policy in force at the time of the transaction and the individual’s circumstances.

Is a main home always exempt from CGT?

Many clients assume that a home they live in is automatically exempt from Capital Gains Tax. In fact, the UK tax system has specific rules for a main residence. Whether relief applies depends on how the property has actually been used and on the tax rules themselves, so no single sentence can cover every case.

Does it make a difference whether the property is held personally or through a company?

Yes. Since 2015 we have found that, for long-term investors, personal ownership and company ownership affect not only the mortgage arrangements but potentially the tax treatment on an eventual sale. We therefore encourage clients not to leave Capital Gains Tax until the property is being sold. Much of the planning belongs at the point the first investment property is bought. In business since 2015: clients think hard about buying, and rarely about selling Since 2015 we have watched many clients spend a great deal of time before a purchase on which area is best, which development has the most growth potential and how to arrange a mortgage. It is often only years later, when they come to sell, that they look properly at Capital Gains Tax for the first time. For a long-term investment, how you plan the purchase and how you plan the sale matter equally.

SJW Practical Tip

If you are buying UK property as a long-term investment, we recommend keeping a complete record from the first purchase onwards: the purchase documentation, legal fees, qualifying improvement expenditure and other relevant paperwork. These records may be valuable when the tax position is worked out on a future sale.

SJW Insight

Since 2015 we have become increasingly convinced that property investment is not a single transaction. It is a process of asset management that runs for many years. Buying, holding, letting, borrowing, selling and tax are all connected. At SJW UK Properties we therefore always encourage clients not to plan only for how they buy today, but to plan in advance for how they will hold and how they will eventually sell. Mature investment planning looks to the final step from the very first day.

Last updated: July 2026

Disclaimer: This article is provided for general information only and does not constitute legal, tax, accounting or investment advice. Capital Gains Tax rules may change as UK legislation changes, and every client’s position is different. Please consult a professional tax adviser or accountant before selling a property, and plan around the policy then in force.