How to use it
- Enter the gain, not the sale price. The gain is the sale price less what you paid, less buying and selling costs, less capital improvements.
- Enter your income before tax for the tax year. The calculator takes off the personal allowance itself to find your taxable income, because that is the figure the 18% and 24% rates (2026/27) are measured against.
- Count the months the property was your only or main residence. Time when it was let out or empty does not count, apart from the last nine months.
- Enter acquisition and disposal dates to fill the ownership period. Check the calculated months for unusual acquisition history.
- Enter your last move-out date to fill the gap before sale. Enter 0 months if you still lived there on completion day. If you lived there in separate spells, enter how many of the final relief months you actually occupied, so no month is counted twice.
- Enter months before moving in only if all the delayed-occupation conditions beside that input are met, including a qualifying event completed before you moved in.
- Tick the boxes that apply, then press calculate.
- Nothing you type leaves your browser.
How the relief is worked out
Private residence relief is a fraction, not a fixed sum. It is the gain multiplied by the qualifying months over the total months of ownership.
Qualifying months are the months it was actually your only or main home, taken together with the last nine months of ownership. The last nine months always qualify whatever the property was used for then, as long as it was your only or main home at some point. They are part of the same period, not an extra nine months added on the end. So if you were still living there when the sale completed, and had lived there for at least nine months, those nine months are already inside the time you lived there and add nothing further. If you moved out first, or lived there for less than nine months, the months of that final period which fall outside your time in the property are extra relief, up to nine months of them.
HMRC's own example makes the point. A house bought in January 2009 and sold in January 2025 is owned for 192 months. The owner lived there throughout apart from nine months in 2011. Relief is 183 of 192 months, not 192 of 192, because the final nine months were months the owner was living there anyway.
In the two rows where the property was let until the sale, the owner had moved out well before completion, so all nine of the final months are extra relief. In the fourth row the owner was still living there at completion and had been for eight years, so the final nine months are already counted in the 96 months of residence and add nothing.
The tax on what is left follows GOV.UK's method. Take the £3,000 annual exempt amount (2026/27) off the gain that is not relieved, work out your taxable income (your income after the £12,570 personal allowance for 2026/27, which reduces by £1 for every £2 of income over £100,000 for 2026/27), then charge the part of the gain that falls within the £37,700 basic rate band (2026/27) at 18% and the rest at 24%.
The final nine months only count if you lived there
A property that was never your only or main residence gets no relief at all, including no final nine months. The nine month rule extends relief for a home you did live in. It does not create relief for one you did not.
If you lived there for less than nine months, the final nine months still qualify, capped by ownership. Residence months outside that final period also count; any overlap is counted once. For example, two months living there at the start of ten years of ownership gives eleven qualifying months if you then moved out until sale.
The final period can be 36 months where the disability or care-home conditions beside the checkbox are met. The property must have been your only or main home at some point.
What this does not cover
- Lettings relief, which since April 2020 only applies where you shared occupancy with the tenant
- Periods of absence that still qualify for relief under the statutory rules, which are not a concession: absences for any reason totalling up to three years, any period spent working outside the UK, and up to four years living away from home for work
- Part of the property used exclusively for business, which is excluded from relief
- Grounds over half a hectare, and second homes where a nomination has been made
- Capital losses brought forward
- Income tax reliefs other than the personal allowance, and pension or gift aid payments that extend your basic rate band
- Non-resident sellers, whose period of ownership and rebasing rules are different
- Multiple occupation periods unless you add the actual months lived there within the final relief period in the optional field. Check unusual periods and qualifying absences with an adviser.
The tapering of the personal allowance above income of £100,000 (2026/27) is applied by this calculator.
Common questions
Do I have to report this even if the relief covers everything?
If the whole gain is covered by private residence relief there is usually nothing to report. Where any capital gains tax is due on a UK residential property, it must be reported and paid within 60 days of completion.
Why does the calculator ask when I moved out?
Because the last nine months of ownership qualify as part of the same period of residence, not as an extra nine months on top. If you were living there when the sale completed, and had been for at least nine months, those months are already counted once. If you moved out two years before completion, nine of those 24 months qualify. Without knowing when you moved out, a calculator cannot tell the two cases apart, and adding nine months to both overstates the relief for anyone who was still living there.
Can a couple each claim the relief?
A married couple or civil partners can only have one main residence between them for this purpose. Each spouse computes their own share of the gain and their own relief on it.
What if I moved out and moved back in?
The qualifying months are added together, so two separate periods of occupation both count. Enter the total in the months of residence field, and put the months between the last time you moved out and the sale completing in the field below it. Enter your actual occupied months within the final relief period in the optional field, so the final 9 or 36 months are not double counted. Check complex absence periods with us.
Does time before I owned it matter?
No. Ownership runs from completion of your purchase to completion of your sale, and only that period is used in the fraction. Ownership before 31 March 1982 is left out, so if you owned the property before then, count from that date.
