Stamp duty is charged in slices, not on the whole price
Stamp duty land tax uses marginal bands, so only the slice of the price inside each band is taxed at that band's rate. A 295,000 pound purchase pays nothing on the first 125,000, 2% on the next 125,000 and 5% on the last 45,000, which is the 4,750 HMRC publishes and the figure this calculator produces.
That matters most just above a threshold: crossing 250,000 does not retrospectively tax the first 250,000 at 5%, a misreading that costs buyers real negotiating room.
The rates here are the standard residential rates for a main home in England and Northern Ireland, in force since 1 April 2025. Scotland charges land and buildings transaction tax and Wales land transaction tax on entirely different scales, and neither is modelled here. First-time buyers pay nothing up to 300,000 and lose the relief altogether on a purchase above 500,000, neither of which is modelled, so the figure shown is the standard rate.
Council tax is a band, not a percentage
England has no annual property tax on value. Council tax is a flat yearly bill set by each council against one of eight valuation bands, and those bands still rest on what a property was worth on 1 April 1991. The calculator therefore asks for a yearly amount rather than a percentage, and opens on the average band D bill in England for 2025-26.
Because the bill is banded, it barely moves with price: band A pays six ninths of the band D bill and band H eighteen ninths, so the cheapest house in the country and the dearest sit a factor of three apart, not a factor of a hundred.
No mortgage insurance, a dearer rate instead
British lenders price the risk of a small deposit into the interest rate rather than charging a separate premium, so there is no PMI-style field on this page. A 95% loan-to-value mortgage is simply quoted at a materially higher rate than a 60% one, and moving down a loan-to-value tier at remortgage is worth more than most fee comparisons.