How the calculator works
It applies the four bands and charges the government confirmed at the Budget for the first year, 2028/29. Charges then rise each year with CPI inflation from 2029/30, so later bills will be a little higher.
| 2026 value | A year | About a month (12 payments) |
|---|---|---|
| £2m to £2.5m | £2,500 | £208 |
| £2.5m to £3.5m | £3,500 | £292 |
| £3.5m to £5m | £5,000 | £417 |
| £5m and above | £7,500 | £625 |
Charges confirmed at the Budget on 28 October 2026 and being legislated in the Finance Bill 2026-27, so not yet law. They rise each year with CPI inflation from 2029/30. Monthly figures are rounded; the consultation proposed 12 monthly instalments, or 10 on request.
It also shows what the charge could add up to over 20 years at 2% and 5% inflation a year, because the surcharge has no end date and rises every year. These are illustrations, not forecasts.
| 2026 value | First year | 20 years at 2% a year | 20 years at 5% a year |
|---|---|---|---|
| £2m to £2.5m | £2,500 | £60,743 | £82,665 |
| £2.5m to £3.5m | £3,500 | £85,041 | £115,731 |
| £3.5m to £5m | £5,000 | £121,487 | £165,330 |
| £5m and above | £7,500 | £182,230 | £247,995 |
Illustration only, not a forecast. Assumes the home stays in the same band from 2028/29 and the charge rises each year by the rate shown: 2% is the Bank of England inflation target, 5% a higher-inflation case. Revaluations every five years could move a home between bands, and money paid in later years is worth less in today's terms.
It flags a home as near a line when your estimate is within 10% of £2m, £2.5m, £3.5m or £5m. That margin is a rule of thumb, not an official test. Valuations of expensive, individual homes can differ by that much between two qualified valuers.
What the result does not tell you
- It is not a valuation. The value that counts will be set by the Valuation Office as at 2026.
- It does not know about your home's quirks. Size, layout, condition, lease length and the quality of nearby sales evidence all move the figure.
- The bands and charges were confirmed at the Budget on 28 October 2026 but are not law until the Finance Bill 2026-27 is passed, and Parliament could still amend them.
If the result is close to a line
This is where the money is. A home valued at £2.05m pays £2,500 a year from the start; at £1.95m it pays nothing. Between the higher bands the step is £1,000, £1,500 or £2,500 a year, every year until at least the 2033 revaluation.
If you are close, the useful work happens now: pinning down the floor area, recording the home's condition as it was in 2026, and finding the sales that best support the right value. Our valuation review does exactly that. You can read more in what if my home is worth just over £2m?
Calculator questions
How accurate is the mansion tax calculator?
It is only as good as the value you enter. It applies the bands and 2028/29 charges confirmed at the Budget on 28 October 2026 to your own estimate. The figure that counts will be the Valuation Office's view of the home's value in 2026.
Why does it ask who owns the home?
Because the owner pays, and the rules treat owners differently. Deferral is tested on a household, so a company is unlikely to qualify, trustees are liable for homes held in trust, and joint owners are each liable for the whole amount.
What value should I enter?
Your best estimate of what the home would have sold for in 2026. Recent sales of similar homes nearby, or a valuation from around that time, are a better guide than an online estimate or an old purchase price.
Last checked against the government's Budget documents and consultation response on 30 October 2026. The surcharge is being legislated in the Finance Bill 2026-27 and is not yet law. Some detail is still to come in regulations.