Buying a home in London often starts with the agreed price and a rough idea of the deposit. Then the wider moving costs come into view. Legal fees, survey costs, mortgage charges, packing, removals, and then the one that catches many buyers off guard: Stamp Duty Land Tax.
That surprise is common, especially when someone is comparing flats in Croydon, family houses in Ealing, or larger homes in Richmond and assumes the tax works as a single percentage. It doesn't. That misunderstanding can throw off a moving budget at exactly the point when decisions need to be clear.
A buyer planning a move in areas such as Walthamstow, Islington or Ruislip usually isn't asking for tax theory. The question is simpler: how is stamp duty calculated, and what does that mean for the total cash needed before moving day? Getting that right matters because SDLT sits alongside the deposit and legal work as an upfront cost, not an optional extra to deal with later.
A guide to understanding your stamp duty bill
A common pattern appears when buyers get close to making an offer. They've checked monthly mortgage payments, spoken to the solicitor, and started thinking about moving dates. Then someone mentions stamp duty, and the numbers suddenly feel less straightforward than the estate agent's listing suggested.
In London, where purchase prices can move quickly from one band to the next, that confusion has real consequences. A buyer looking at a flat in Lewisham one week and a house in Ealing the next may be dealing with a very different tax bill, even before the first box is packed. The issue isn't just the amount itself. It's when that cost needs to be available and how it affects the rest of the moving budget.
Practical rule: treat stamp duty as part of the move budget from the start, not as a last-minute legal extra.
The reassuring part is that the calculation follows a clear structure. Once a buyer understands that SDLT is charged in slices of the purchase price rather than as a single flat rate on the total amount, the picture becomes much clearer. That makes it easier to budget for removals, storage, if needed, and other costs that arise around completion.
What is Stamp Duty Land Tax
Stamp Duty Land Tax, usually shortened to SDLT, is the tax a buyer pays when purchasing property or land in England and Northern Ireland. It sits separately from the deposit, the mortgage, and the solicitor's own fees. In practical terms, it's one of the key sums that must be budgeted for before a move can proceed smoothly.
Many buyers assume the tax works like a single percentage applied to the full purchase price. That's the wrong way to think about it. A better comparison is income tax. Different portions of the purchase price fall into different bands, and each band is taxed at its own rate.
The point most buyers need to grasp
When clients ask how stamp duty is calculated, the most useful answer is this: the purchase price is divided across tax bands. The buyer doesn’t pay one single rate on the whole price unless the whole price falls within one band that happens to apply in full. In most ordinary purchases, the tax is layered.
That’s why two buyers can look at homes with fairly similar asking prices and still end up with noticeably different SDLT bills. The threshold matters, but so does where each slice of the price lands.
A related moving cost that often causes confusion is council tax at the new address. Anyone planning the full household budget alongside SDLT may find our guide to council tax when moving home useful.
Why landlords and investors need to read the rules more carefully
For owner-occupiers, the basic mechanics are usually the main concern. For landlords and buyers of additional property, the details matter even more because surcharges and relief rules can change the final bill. Knight Frank’s explanation of how stamp duty is calculated sets out the surcharge position clearly for buyers weighing up an additional purchase.
SDLT is paid by the buyer and should be treated as part of the funds required to complete, not as a background admin detail.
How stamp duty is calculated with current 2026 rates
A buyer agrees a price on a flat in London, lines up the deposit, pays for the survey, starts comparing removal quotes, then realises the money needed on completion is still short. In practice, SDLT is often the gap. It has to be budgeted as part of the move, not treated as a small legal extra.
For standard residential purchases in England and Northern Ireland, SDLT is charged in bands. The current 2026 structure is 0% on the first £125,000, 2% on the next £125,000, 5% on the next £675,000, 10% on the next £575,000, and 12% on anything above £1.5 million, in line with HMRC’s official guidance on residential property SDLT rates.
The standard residential bands
| Portion of purchase price | Rate |
|---|---|
| First £125,000 | 0% |
| £125,001 to £250,000 | 2% |
| £250,001 to £925,000 | 5% |
| £925,001 to £1.5 million | 10% |
| Above £1.5 million | 12% |
A worked example using a purchase price of £300,000
A £300,000 purchase is calculated in slices, not as one block:
- First £125,000 at 0% = £0
- Next £125,000 at 2% = £2,500
- Remaining £50,000 at 5% = £2,500
Total SDLT: £5,000
That method matters because London buyers regularly sit close to a band threshold. A small change to the agreed price does not affect the tax on the entire purchase. It changes the tax only on the slice that falls into the higher band. That is why a buyer can negotiate an extra £10,000 on price without triggering a dramatic jump in the final SDLT bill.
Where buyers go wrong
The usual mistake is applying one rate to the full purchase price. A £250,000 home is not taxed at 2% across the whole amount. The first £125,000 is exempt from SDLT, and only the next £125,000 is taxed at 2%, resulting in an SDLT bill of £2,500.
The second mistake is planning for the purchase but not for the move around it. In London, SDLT can sit alongside the deposit, solicitor's costs, mortgage fees, removals, packing materials, temporary storage, and overlap costs if the buyer is leaving a rental or managing a chain.
Treat SDLT as completion money. If it is missing from the budget, every other moving decision gets tighter.
Worked examples for typical London property prices
Once the tiered method is clear, the next step is to apply it to the range of prices buyers see across London. The figures below use common London scenarios rather than abstract textbook examples. The boroughs are only there to make the examples feel familiar. The tax is still calculated by band, not by location.
Example one: a flat in Croydon or Lewisham at £350,000
A one-bedroom or compact two-bedroom flat in parts of south London can easily sit around this level.
The SDLT is worked out as follows:
- First £125,000 at 0% = £0
- Next £125,000 at 2% = £2,500
- Remaining £100,000 at 5% = £5,000
Total SDLT: £7,500
For a buyer planning to move from rented accommodation into a first-owned home, this matters because it can be added to the deposit, legal work, and the practical cost of vacating the old place. If the completion date is tight, that can shape every other moving decision.
Example two: a family home in Walthamstow or Ealing at £750,000
This sort of purchase is where the tiered structure becomes especially important, because a large part of the price falls into the 5% band.
The SDLT works like this:
- First £125,000 at 0% = £0
- Next £125,000 at 2% = £2,500
- Remaining £500,000 at 5% = £25,000
Total SDLT: £27,500
This is often the point at which buyers realise the tax bill can materially affect their available cash before the move. A family upgrading within London might be dealing with school timing, parking restrictions on moving day, and overlapping keys for two addresses. SDLT doesn’t replace those pressures, but it does need to be funded before the move can properly happen.
Anyone benchmarking values in stronger parts of the capital may find Luxury Homes London useful for gauging how quickly asking prices move into higher SDLT bands. Our guide to London house moves covers the logistics side once the property figures are clear.
Example three: a larger property in Richmond or Islington at £1.2 million
At this level, the purchase crosses into the 10% band for the upper slice.
The SDLT calculation is:
- First £125,000 at 0% = £0
- Next £125,000 at 2% = £2,500
- Next £675,000 at 5% = £33,750
- Remaining £275,000 at 10% = £27,500
Total SDLT: £63,750
That doesn’t mean the whole £1.2 million is taxed at 10%. Only the portion above £925,000 falls into that band. That distinction is exactly why the marginal method matters.
Buyers usually budget more accurately once they stop asking “what rate am I paying?” and start asking “which slices of the price fall into which bands?”
Common stamp duty reliefs and surcharges you should know
A buyer can calculate the standard SDLT bands correctly and still budget the wrong amount for completion. In London, that happens most often where reliefs or surcharges apply, because the purchase price alone does not settle the bill.
The points that most often change the figure are first-time buyer relief, the higher rate for an additional property, and leasehold rent rules. These include the return of first-time buyer relief to a £300,000 nil-rate threshold from 1 April 2025, 5% charged on the portion from £300,001 to £500,000 for qualifying purchases, the usual extra 5% surcharge for additional residential properties, and the separate leasehold SDLT charge on rent where the net present value exceeds £125,000, charged at 1% on the amount above that level.
First-time buyer relief
For qualifying first-time buyers, relief can significantly reduce the SDLT bill. The purchase must be £500,000 or less, and the nil-rate part of that relief is £300,000 under the current rules.
That matters in London because many first purchases sit close to that ceiling. A buyer looking at a flat in places such as Walthamstow, Leyton, or parts of Croydon may qualify, while a similar buyer stretching above £500,000 loses the relief entirely. That is the sort of pricing line buyers need to spot early, before agreeing a figure that looks manageable on mortgage repayments but pushes the tax bill higher than expected.
Worked example: a first-time buyer purchases a property for £500,000.
- 0% on the first £300,000 = £0
- 5% on the remaining £200,000 = £10,000
Total SDLT: £10,000
Additional property surcharge
Buyers who already own another residential property will usually pay an extra 5% on top of the standard residential rates. In practice, this catches buy-to-let purchases, second homes, and some onward movers who have not yet sold their existing home by completion.
This is often the surcharge that most sharply disrupts the moving budget. Buyers tend to focus on the deposit, legal fees, and removals, only to realise late in the process that keeping hold of one property, even for a short period, can significantly change the SDLT position. In London, where purchase prices are already high, that extra charge can absorb money that had been set aside for storage, repairs, or furnishing the new place.
Buyers who sell their previous main residence within 36 months of completing the new purchase can usually reclaim this surcharge, so it's worth checking the refund rules with a conveyancer if the timing applies.
Leasehold rent rules
Leasehold purchases can bring a second SDLT calculation on the rent as well as the premium. If the net present value of the rent goes above £125,000, SDLT is charged at 1% on the amount over that threshold.
This does not affect every flat purchase, but it should never be waved through as a minor detail. Buyers of leasehold property should ask their solicitor to confirm exactly whether the SDLT estimate covers only the purchase price or also includes any tax due on the lease rent. That check matters more in London than many buyers expect, because flats make up such a large part of the market.
Reliefs and special cases that need individual advice
Some transactions involve other reliefs or special rules, including shared ownership and properties bought by non-UK residents, who face an additional 2% surcharge on top of any other applicable rates. These cases depend on the structure of the deal, the buyer’s circumstances, and how the purchase is being completed. A label on an online calculator is not enough.
The practical answer is simple: ask the conveyancer to set out the SDLT position in writing and confirm what assumptions they have used. Stewart Accounting Services has a useful note on the kind of late-stage property tax surprises this can catch out.
Reliefs and surcharges are often what separate a workable London moving budget from a last-minute cash shortfall.
Putting it into practice: your next steps
Understanding the formula is useful. Turning it into a reliable moving budget is what helps.
Who handles payment
In most purchases, the solicitor or conveyancer deals with the SDLT submission and payment as part of the completion process. SDLT returns must be filed and the tax paid within 14 days of completion. Buyers should still read the paperwork carefully. An estimate isn't the same thing as a confirmed calculation, particularly where leasehold terms, first-time buyer status, or an additional property surcharge may apply.
Why timing matters
SDLT is not the kind of cost that can be left floating while the move is organised. It sits in the same practical planning window as transfer funds, key release, and completion-day arrangements. If the tax figure changes late, it can tighten the rest of the move budget very quickly.
Buyers usually cope best when they treat SDLT as one of the completion funds to verify early, not one of the admin details to tidy up later.
For the final check, the official HMRC SDLT calculator should be the reference point, with the solicitor confirming the exact position for the transaction.
Planning your move with confidence
The key point is simple. Stamp duty is calculated in bands, not as a single flat percentage of the whole purchase price. Once that is understood, the bill becomes much easier to follow. The final amount then depends on the purchase price and on the buyer’s own position, especially where first-time buyer relief, an additional property surcharge, or leasehold rent rules may apply.
For anyone asking how stamp duty is calculated as they’re planning a London move, the most useful approach is to treat SDLT as part of the completion funds from the outset. Check the official calculator, ask the conveyancer to confirm the exact figure, and keep that amount separate from the rest of the moving budget.
Once the SDLT figure is understood, the rest of the move tends to become easier to organise. Dates, access, packing, and transport all sit on firmer ground when the finances are realistic.
If the purchase budget is now taking shape and the next step is organising the actual move, we can help plan the practical side, from flat and house removals across London to packing, storage support, and clear written quotations based on the details of the move.
This guide provides general guidance on how Stamp Duty Land Tax is calculated. It is not financial or legal advice. For advice specific to your circumstances, contact your solicitor, conveyancer, or HMRC directly.
