Why isn't stamp duty just one flat rate on my purchase price?

SDLT works like income tax, not like VAT. You don't pay one rate on the whole price. Instead, you pay increasing rates on the slice of the price that falls into each band, and only that slice. For a standard residential purchase (not a first-time buyer, not an additional property), the bands are: 0% up to £250,000, 5% from £250,000 to £925,000, 10% from £925,000 to £1.5m, and 12% above that.

Take a home mover buying at £350,000. The first £250,000 is taxed at 0%, so £0 is due on that portion. The remaining £100,000 (the slice from £250,000 to £350,000) is taxed at 5%, which is £5,000. Total SDLT due: £5,000, not the £17,500 you'd get by wrongly applying 5% to the entire price.

So what for you: if you've mentally budgeted stamp duty by applying the top rate to your whole purchase price, you've almost certainly overestimated your bill. Run the exact figure through the calculator above before you rule a property out on cost.

First-time buyer relief: how much it saves, and exactly where it stops

If you and everyone else on the purchase qualify as a first-time buyer, and the property costs £625,000 or less, different bands apply: 0% up to £425,000, then 5% from £425,000 to £625,000. Above £625,000, the relief disappears entirely and standard bands apply to the whole price instead. This is a genuine cliff edge.

A first-time buyer purchasing at £500,000 pays 0% on the first £425,000 and 5% on the remaining £75,000, which is £3,750 in total. Compare that with the £12,500 a non-first-time buyer would pay on the same £500,000 under standard bands: the relief is worth £8,750 here. But push the price just over the threshold and the picture flips fast. At £625,000, relief still applies and the bill is £10,000. At £626,000 (just £1,000 more), relief is gone, standard bands kick in, and the bill jumps to £18,800. That's an £8,800 increase in stamp duty for a £1,000 increase in price.

So what for you: if you're a first-time buyer negotiating anywhere near £625,000, the maths points toward holding the line on price rather than letting it drift a few thousand pounds over that threshold. The stamp duty jump alone could wipe out any goodwill you gained in negotiation.

Buying a second property or a buy-to-let? Here's what the 3% surcharge really costs

Additional properties (buy-to-lets, second homes, holiday lets) pay the standard bands plus a flat 3% surcharge added to every single band, including the portion that would otherwise be tax-free. Because the surcharge applies at the same 3% rate right across the price, the total extra cost it adds always works out to roughly 3% of the full purchase price, regardless of how it's split across bands.

Worked example: £300,000 buy-to-let purchase

Surcharged bands: 3% on the first £250,000 = £7,500. 8% (5% standard + 3% surcharge) on the remaining £50,000 = £4,000. Total SDLT due = £11,500. A home mover buying the identical £300,000 property under standard bands would pay £2,500, a £9,000 gap that comes entirely from the surcharge, which is almost exactly 3% of £300,000.

So what for you: if you're weighing a buy-to-let purchase, that surcharge needs to sit in your yield calculation from day one, not as an afterthought. Most people who run these numbers end up folding the SDLT hit into their break-even rent target before they make an offer, not after.

Scotland and Wales use completely different rules

This calculator covers England and Northern Ireland only, where SDLT applies. Scotland charges Land and Buildings Transaction Tax (LBTT), with its own bands and its own Additional Dwelling Supplement for second properties and buy-to-lets. Wales charges Land Transaction Tax (LTT), also with separate thresholds and a separate higher-rate surcharge for additional properties. Neither uses the £250,000 nil-rate band or the £625,000 first-time buyer cliff edge described above. These are genuinely different systems.

So what for you: if the property you're looking at is in Scotland or Wales, the figures on this page won't apply to your purchase. Check the equivalent LBTT or LTT calculator before you budget, rather than assuming England's thresholds carry across the border.

What this means for you

SDLT thresholds move with the Budget more often than most buyers expect. The bands used on this page are the ones currently in force, but always check GOV.UK for the rates that apply on your actual completion date, particularly if completion is months away. Once you've got your SDLT figure, it's only one part of your affordability picture: run the same purchase price through our mortgage repayment calculator to see the monthly cost, and if you're not yet sure how much you can borrow in the first place, our affordability calculator will give you a realistic ceiling before you factor stamp duty in on top.

If you're a first-time buyer sitting close to the £625,000 relief cliff, or a landlord about to absorb the 3% surcharge, the maths points toward getting the exact SDLT figure locked in before you make an offer, not after, when it's harder to walk away from a price that no longer works.