SolvedSDLTM13085 | Calculation of Stamp Duty Land Tax (SDLT): Rent: Term includes a part year
From HM Revenue & Customs · Stamp Duty Land Tax Manual
For the purposes of calculating stamp duty land tax, if the term of the lease includes a part year, the annual rent should be apportioned to the number of days in the part year. The part year will always fall at the end of the lease for the purposes of calculating net present value.
Refer to SDLTM13090 and SDLTM13095 onwards for examples.