Land Transaction Tax, LTT, is what you pay when you buy a home in Wales. It took over from Stamp Duty Land Tax there in April 2018 and is collected by the Welsh Revenue Authority. It is a marginal tax: each band's rate applies only to the slice of the price that falls inside it.
The main residential rates on the Welsh Government's table, unchanged since 10 October 2022, are nothing up to £225,000, 6% on the part to £400,000, 7.5% to £750,000, 10% to £1.5 million and 12% above. A £300,000 home therefore pays 6% on the £75,000 above the nil band, which is £4,500. The same purchase in England would pay £5,000 before any first-time buyer relief.
The Welsh nil band applies to every buyer, not only first-time buyers, so many cheaper homes pay nothing at all. Above it the rates climb faster than in England: by £400,000 the Welsh bill is £10,500 against £10,000 under SDLT.
The higher residential rates apply when you buy an additional home, such as a second property or a buy-to-let. Since 11 December 2024 they run from 5% on the first £180,000 up to 17% above £1.5 million, according to the same table, so on a £200,000 buy-to-let the bill is £9,000 plus £1,700, £10,700 in all.
The British setting in the mortgage calculator uses the English and Northern Irish scale and does not model LTT. For a Welsh purchase, work the tax out from the bands above and use it in place of the transfer-tax figure the calculator shows.