Capital Gains Tax on Rental Property UK Explained

Selling a buy-to-let can release a useful lump sum, but the money arriving from the solicitor is not the same as the profit you keep. Capital gains tax on rental property UK rules can catch landlords out when a sale has moved quickly, especially if the 60-day reporting deadline has not been planned for.

For many landlords, the best time to think about capital gains tax is well before an offer is accepted. Good records, a clear calculation and sensible timing can make a meaningful difference to the bill. Leave it until completion, and choices become far more limited.

When capital gains tax applies to a rental property

Capital gains tax, usually shortened to CGT, may be due when you dispose of a property that has risen in value. A disposal includes a sale, but can also include giving a property away, transferring it to someone other than a spouse or civil partner, or exchanging it for another asset.

A property let out as a buy-to-let is normally subject to CGT on any gain. The tax is based on the increase in value, not the full sale price. If you bought a flat for £250,000 and sell it for £400,000, the starting point is a £150,000 gain before allowable costs and reliefs are considered.

The position can be more complicated where a property has been both your home and a rental. You may be entitled to Private Residence Relief for the period you genuinely lived there as your main residence, plus the final nine months of ownership in many cases. The details matter, particularly if you moved out before letting the property, used part of it exclusively for business, or owned more than one home.

How capital gains tax on rental property UK is calculated

The basic calculation is straightforward on paper:

Sale proceeds less purchase price, allowable buying and selling costs, and qualifying improvement costs equals the gain.

From there, any available reliefs and your annual tax-free allowance are applied. For the 2025/26 tax year, the annual exempt amount for an individual is £3,000. The remaining taxable gain is then charged at the relevant residential property CGT rates.

For individuals, gains falling within unused basic rate income tax band are generally taxed at 18%. Gains above that band are generally taxed at 24%. Your salary, self-employed profit, dividends, pension income and other taxable income all affect how much of the gain falls into each band.

That is why two landlords selling similar properties can face very different tax bills. A landlord with low income in the year of sale may have more gain taxed at 18%. A company director taking a large dividend, or a self-employed contractor having a strong year, may find most of the gain falls at 24%.

A simple example

Suppose a landlord bought a rental house for £300,000 and sells it for £450,000. They paid £6,000 in stamp duty and legal fees when buying, £7,000 in estate agent and legal fees on sale, and spent £20,000 on a qualifying extension.

Their gain before the annual exemption would be £117,000:

£450,000 less £300,000, less £6,000, less £7,000, less £20,000.

After the £3,000 annual exemption, the taxable gain is £114,000. The actual tax depends on the landlord's taxable income for that year and whether any part of the gain can use their unused basic rate band.

This is an illustration, not a calculation to rely on for a live sale. Dates, ownership shares, past use of the property and the exact nature of expenditure can all change the result.

Costs you can usually deduct

Landlords often underclaim because paperwork from years ago has been misplaced or because they assume every property expense is treated the same way. CGT allows certain capital costs to reduce the gain, but it does not allow routine running costs simply because the property was let.

Costs that may be allowable include the purchase price, Stamp Duty Land Tax, solicitor's fees and survey fees connected with the purchase, estate agent and legal fees on sale, and the cost of improvements that add value or have a lasting benefit. An extension, a new conservatory or converting a loft may qualify if the work is capital in nature.

Repairs are different. Replacing broken tiles, repainting between tenancies or fixing a boiler is normally revenue expenditure. These costs may have been relevant to rental income tax while the property was let, but they will not usually reduce a capital gain on sale. Likewise, mortgage interest and mortgage arrangement fees do not reduce CGT.

Keep invoices, completion statements and evidence of payment. If HMRC asks questions, a rough estimate of work done 12 years ago is far less persuasive than a clear file showing what was spent and why.

Timing a sale can affect the tax

The tax year runs from 6 April to 5 April. Where you have a degree of control over the timing of a sale, exchanging contracts before or after the tax year end can alter the result. You may be able to use an annual exemption in one year rather than another, or avoid stacking a large gain on top of unusually high income.

For jointly owned property, each owner is taxed on their own share of the gain. Married couples and civil partners can sometimes transfer an interest between themselves without an immediate CGT charge, but this needs looking at before contracts are exchanged. It is not a last-minute fix, and other taxes and legal ownership arrangements must be considered.

If you own several assets, you may also have scope to crystallise a capital loss in the same tax year to offset part of the property gain. Selling an investment simply for tax reasons is rarely wise, but known losses should not be ignored when planning a disposal.

Reporting and paying HMRC after completion

If UK Capital Gains Tax is due on the sale of UK residential property, you normally need to report the disposal and make a payment on account within 60 days of completion. This is separate from your usual Self Assessment tax return.

The 60-day return requires a reasonable estimate of the gain and tax due. You then include the disposal on your Self Assessment return if you normally complete one, or if required to do so. Any final adjustment is made through that process once your full income position for the tax year is known.

Missing the deadline can lead to penalties and interest. This is particularly frustrating because the information needed is usually available from the conveyancer, your purchase paperwork and your records. The practical point is to involve your accountant as soon as a sale looks likely, rather than waiting for the keys to change hands.

Situations that need extra care

Some rental-property sales are not routine. A former family home that was later let, a property inherited from a parent, a transfer to a family member, or a flat owned through a limited company all need a tailored review.

Inherited property is generally treated as acquired at its market value at the date of death, rather than at the price the deceased paid. A gift can still create a CGT charge based on market value, even if no money changes hands. And where a company owns the property, corporation tax and the way sale proceeds are extracted from the company create a different set of decisions.

Letting Relief is another area where old assumptions cause problems. It is now limited and will generally only apply where the owner shared occupation of the property with a tenant. Do not assume it is available simply because the property was once your home and was later rented out.

Plan before the property goes on the market

A sale is often driven by a change in circumstances: clearing a mortgage, funding retirement, reducing a portfolio, or moving capital into the business. Tax should not dictate every decision, but it should be part of the numbers from the start.

Short And Sons Accountants can help landlords establish the likely gain, identify the records needed and prepare for the 60-day reporting requirement. A clear estimate before exchange gives you time to make decisions with your eyes open, rather than finding a sizeable tax payment waiting just after completion.