SDLT Calculator.

Methodology

Rates last verified 16 May 2026.

What the calculator does

For a given purchase price and buyer type, the calculator computes SDLT band by band against the current HMRC schedule and returns a single total plus the breakdown that produced it. The same engine runs at build time (for the static price-point pages) and in your browser when you change an input, so the numbers are identical regardless of how you got here.

Rates and rules applied

  • standard residential bands as set out in /sdlt-rates/
  • first-time buyer relief up to £500,000, with the cliff withdrawal above that
  • 5% additional-property surcharge above the £40,000 threshold, applied to every band
  • 2% non-UK resident surcharge, stacking on top of the additional surcharge if both apply
  • 17% corporate flat rate for purchases over £500,000 (with standard rates plus surcharge below)
  • mixed-use / non-residential bands when the mixed-use option is selected

Sources

Rates come directly from HMRC. Our primary references are:

Update process

SDLT rates change at fiscal events, not on a fixed schedule. When a Budget or other fiscal statement affects SDLT we aim to update the calculator within two hours of the announcement:

  1. read the precise change in the official documents
  2. update the rate tables in the calculator engine
  3. run the full test suite to confirm nothing else breaks
  4. update the "last verified" date in the footer and deploy

Historic regimes are retained so the calculator can be used to check prior-period purchases.

What this calculator does not do

  • it does not advise on whether your purchase qualifies for FTB relief, the additional-property surcharge or the corporate reliefs, those are factual judgements
  • it does not cover land transactions outside England and Northern Ireland (use LBTT for Scotland, LTT for Wales)
  • it does not handle linked transactions or complex multi-dwelling deals where SDLT is calculated on combined consideration
  • it is not financial advice, for anything material, ask your conveyancer or a tax adviser

Errors and corrections

If you spot a mistake in a rate, threshold, or surcharge, please email hello@stampdutyguide.co.uk. We treat accuracy as the central feature of this tool and fix issues quickly.