Split the price into bands
For a standard-rate £350,000 purchase in England or Northern Ireland, split the price into £125,000, another £125,000, and the remaining £100,000. Multiply those portions by 0%, 2% and 5%. Add the resulting £0, £2,500 and £5,000 to get £7,500.
Applying 5% to the whole £350,000 would give £17,500, which is not the standard residential calculation. The top marginal rate describes the last slice of the price, not every pound spent.
Marginal rate versus effective rate
The effective rate is total tax divided by the purchase price. In the £350,000 example, £7,500 divided by £350,000 is about 2.14%. The marginal rate on an extra pound within that band is 5% before final rounding.
This distinction helps when comparing offers. Increasing a standard-rate price from £350,000 to £360,000 increases SDLT by £500, because the additional £10,000 stays within the 5% band. It does not cause the earlier bands to be recalculated at 5%.
Change the rules before doing the arithmetic
First decide the jurisdiction and buyer category. First-time buyer relief changes the starting bands, while additional-property and non-resident rules can increase the applicable percentages. Scotland’s ADS is a separate charge on the full price. Wales has a separate higher-rate schedule.
The SDLT first-time buyer price limit is a notable exception to a smooth marginal increase: exceeding £500,000 removes the relief. Compare both sides of that limit rather than adding 5% of only the amount above it.
Rounding and the purchase price entered
The final SDLT amount is rounded down to the nearest pound. For instance, a £350,001 standard-rate purchase produces £7,500.05 before rounding and a £7,500 total. The calculator displays the band amounts before applying final whole-pound rounding.
Enter the actual chargeable purchase consideration, not the deposit or mortgage loan. Transfers, debt assumptions, linked purchases and leases can change what counts as consideration. Those cases need a more specific assessment than entering a house’s headline market value.
RESEARCH & CORRECTIONS
Sources and review
Researched and maintained by StampDutyCal. Checked on against the official sources below. This is our own research, not an independent professional tax review. We update the website when rules change.