Methodology
How we calculate
One calculation engine, localised per country. Every rate lives in a dated rate file cited to the tax authority, never hard-coded in the logic and never taken from memory.
The engine
A single pure function takes your figures plus a country's ruleset and returns the estimate. The function contains no tax rates at all. That means keeping the site current is a data change, checked against the official page, not a rewrite of the maths.
United Kingdom, 2026/27
Gain equals sale price minus purchase price, allowable buying and selling costs and capital improvements. Private Residence Relief covers the months a property was your main home plus the final 9 months. We then deduct the annual exempt amount of £3,000 and tax the rest at 18% within your remaining basic-rate band (£37,700) and 24% above it. UK residential gains must be reported and paid within 60 days of completion.
| Capital Gains Tax rates and allowances |
| Tax when you sell property (60-day reporting) |
| Private Residence Relief (HS283) |
United States, 2026
Gain equals the sale price minus the adjusted basis (purchase price, improvements and costs). A property held more than a year is a long-term gain, taxed at 15% or 20% depending on where it stacks on your taxable income, with a 0% band at the lowest incomes. A main home can exclude up to $250,000 of gain, or $500,000 for a couple, under Section 121. The Net Investment Income Tax adds 3.8% above $200,000 of income ($250,000 married), and rental depreciation is recaptured at up to 25%. State tax is separate. The 2026 rate thresholds come from Revenue Procedure 2025-32.
| Topic 409, Capital gains and losses |
| Revenue Procedure 2025-32 (2026 rate thresholds) |
| Topic 701, Sale of your home (Section 121) |
| Net Investment Income Tax |
Ireland, 2026
Gain equals the sale price minus the purchase price, the costs of buying and selling and enhancement expenditure. Where the purchase was made in 2002 or earlier, the purchase price and buying costs are multiplied by Revenue's indexation factor for that year before the gain is worked out. Principal Private Residence relief exempts the fraction of the gain covering the years the property was the seller's main home plus the final 12 months. Each individual deducts the €1,270 personal exemption, and the rest is taxed at 33%. Payment is due by 15 December for sales from January to November and by 31 January for December sales. The engine reproduces Revenue's published worked example to the cent.
Australia, 2026-27
Capital gain equals the sale price minus the cost base (purchase price, buying and selling costs and capital improvements). The main residence exemption removes the share of the gain for the days the property was the seller's home, worked out by contract dates, and a former home let out after moving out stays exempt for up to 6 years under the six-year rule. A property held at least 12 months has the remaining gain reduced by 50%. The net capital gain is added to other taxable income and taxed at the 2026-27 resident rates (15% above $18,200, 30% above $45,000, 37% above $135,000 and 45% above $190,000) plus the 2% Medicare levy. The engine reproduces the ATO's published Farnaz, Peter and Roya examples. The Budget 2026-27 change to the discount from 1 July 2027 is noted on the page and not yet applied.
Canada, 2026
Capital gain equals the proceeds of disposition minus the adjusted cost base and the outlays and expenses of selling. The principal residence exemption removes the gain multiplied by one plus the years designated, divided by the years owned (Folio S1-F3-C2, paragraph 2.20). One-half of the remaining gain is the taxable capital gain, added to income and taxed at the 2026 federal rates (14% to 33%) and the province's own rates, with the 16.5 per cent abatement of federal tax for Quebec residents. A residential property held under 365 days falls under the flipping rule and is fully included as business income. The proposed increase of the inclusion rate to two-thirds was cancelled on 21 March 2025.
UK rates verified 2026-09-03 against HM Revenue & Customs (gov.uk); US rates verified 2026-09-06 against Internal Revenue Service (IRS); Ireland rates verified 2026-09-06 against Revenue (revenue.ie); Australia rates verified 2026-09-06 against Australian Taxation Office (ato.gov.au); Canada rates verified 2026-09-06 against Canada Revenue Agency (canada.ca). Other countries publish once their rate file is verified the same way. Each tool shows its own “rates current as of” date, and the rate update log lists every country's last check.