Data Sources
Our calculator uses official data from authoritative government sources to ensure accuracy.
Primary Sources
- HM Revenue & Customs (HMRC) - Official SDLT rates and guidance
- GOV.UK - Policy announcements and rate changes
- HM Treasury - Budget documents and tax policy
Rate Updates
We monitor official sources for rate changes and update the calculator accordingly. The current rates reflect those effective from 1 April 2025.
Calculation Methodology
All calculations follow HMRC guidance for SDLT computation, including proper handling of bands, rates, and reliefs.
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