Stamp Duty Land Tax (SDLT) is a tax in the United Kingdom that is paid on the purchase of land or property. It is calculated as a percentage of the purchase price, and the rate of the tax varies depending on the value of the property and the purpose of the purchase.

The rate of SDLT for residential properties is based on a tiered system, where the percentage of tax increases as the purchase price of the property increases. For example, for properties purchased for £500,000 or less, the rate of SDLT is 2%, but for properties purchased for more than £500,000 the rate increases to 5%.

For non-residential properties and mixed use properties, the rates are different, for example for purchase under £150,000 the rate is 0% and for purchase above £150,000 it is 2%

It's worth noting that there are certain exemptions and reliefs available that can reduce or eliminate the amount of SDLT that is owed, such as the first-time buyer's relief, which is available for first-time buyers purchasing properties of £300,000 or less, and the additional rate of 3% surcharge for second home and buy to let properties.

In addition, there are different rules and rates for the purchase of Leasehold property and the transfer of a leasehold interest. It is always recommended to consult with a tax professional before making a property purchase, to understand the specific details and how it applies to your individual situation.