Buy-to-let stamp duty refers to Stamp Duty Land Tax (also known as SDLT), that is applied to a property intended for rental purposes.

There is a minimum 3% SDLT surcharge if your buy-to-let purchase results in your owning more than one property.

If you’re purchasing your first (and only) property, and intend to rent it out, you’ll be liable to pay the standard residential stamp duty rates....

When purchasing in England or Northern Ireland you need to pay your BTL stamp duty to HMRC within 14 days from the date of completion/date of entry...