How to use this UK property CGT calculator
This tool gives a quick estimate of Capital Gains Tax (CGT) when you sell a property that is or was your main home. It works by calculating your gain (sale price minus purchase price), then adjusting that figure for allowable costs and Private Residence Relief (PRR) to show the potential amount of CGT due.
If you’re unsure what to enter, start with the basics (purchase price, sale price, purchase date, sale date) and add costs you can evidence, such as legal fees, SDLT on purchase, estate agent fees on sale, and qualifying improvement costs. HMRC generally treats repairs and maintenance as non-allowable for CGT, while capital improvements (for example, an extension or major upgrade that adds value) may be allowable.
Private Residence Relief explained (PRR)
PRR can reduce (or sometimes eliminate) CGT if the property was your only or main residence for part or all of the ownership period. In simple terms, PRR usually covers the period you lived in the home, plus an additional “final period exemption” at the end of ownership even if you weren’t living there at the time of sale. For most cases, the final period is 9 months.
This calculator uses your move-in and move-out dates (if provided) to estimate how much of the total ownership period qualifies for PRR, then applies that relief to reduce the taxable gain.
Rates, allowances, and why your income matters
CGT on residential property for individuals is typically charged at 18% and 24%, depending on how much of your gain falls within the basic-rate band once your taxable income is taken into account. That’s why the calculator asks for your taxable income in the year of sale.
You also usually get an Annual Exempt Amount (tax-free CGT allowance). For the 2025/26 tax year, this is £3,000 per person (so joint owners may benefit from two allowances, depending on ownership and circumstances).
A common “gotcha”: reporting within 60 days
Even if you normally complete Self Assessment later, HMRC may require you to report and pay CGT on UK residential property within 60 days of completion (for sales completing on or after 27 October 2021). Missing the deadline can lead to interest and penalties.
Quick FAQ
Do I pay CGT when selling my main home?
Often no, because PRR may cover the whole gain. CGT is more likely if you didn’t live there for the full period, used it for business, or it wasn’t always your main residence.
Does lettings relief apply if I rented the property out?
Lettings relief is now limited in most cases and is typically only available where the owner shared occupancy with the tenant under modern rules.
Is this calculator exact?
It’s an estimate. PRR elections, periods of absence, transfers between spouses, and mixed-use properties can change the outcome. For a final figure, consider professional advice or HMRC guidance.
