UK Stamp Duty Calculator — Methodology

Last verified 5 May 2026 against HMRC SDLT, Revenue Scotland LBTT, and Welsh Government LTT guidance. Calculator at /uk/property/stamp-duty-calculator/.

What this calculator does

Calculates SDLT (England & Northern Ireland), LBTT (Scotland) or LTT (Wales) on a residential property purchase, applying first-time buyer relief and the additional-dwelling / second-home surcharge where relevant.

The formula

Tax = sum over bands b of:
       max(0, min(price, b.upTo) - b.from) × b.rate

England / NI standard bands (2026/27):
  0% to £125,000, 2% to £250,000, 5% to £925,000,
  10% to £1,500,000, 12% above

England first-time buyer relief (price ≤ £500,000):
  0% to £300,000, 5% to £500,000

Additional dwelling surcharge (England):
  +5% on the whole price when price ≥ £40,000

Scotland (LBTT) and Wales (LTT) use jurisdiction-specific
band tables — see the source CSVs.

Authoritative sources

• SDLT residential property rates
• SDLT first-time buyers' relief
• Higher rates for additional dwellings
• Revenue Scotland LBTT
• Welsh Government LTT rates and bands

Assumptions and limitations

• Residential transactions only. Non-residential and mixed-use rates are out of scope.
• Multiple dwellings relief (MDR) was abolished from 1 June 2024 and is not modelled.
• The non-UK resident 2% SDLT surcharge is available as an option but applies only where the buyer meets the residence test in HMRC guidance.
• Linked transactions and partnership purchases are not modelled.
• LBTT first-time buyer relief and Welsh higher-rate band logic follow the band tables exactly as published.

Source data

The rates used by this calculator are exported as machine-readable CSVs:

• SDLT bands 2026/27 /data/sdlt-2026-27.csv
• LBTT bands 2026/27 /data/lbtt-2026-27.csv
• LTT bands 2026/27 /data/ltt-2026-27.csv

These CSVs regenerate automatically from our canonical rate data at every build, ensuring the calculator output and the published rate data stay in sync.

Verification log

• 5 May 2026: SDLT/LBTT/LTT bands verified against HMRC, Revenue Scotland, and Welsh Government publications